PAK FA, T-50: News #1

So Indian FGFA demands are more strigent than Russian PAK-FA.

I think the FGFA will be superior to the RuAF PAK-FA

Austin wrote:So Indian FGFA demands are more strigent than Russian PAK-FA.
I think the FGFA will be superior to the RuAF PAK-FA

Thanks for sharing the article Austin .

They (IAF) keep on using the term "stringent" again & again but fails short to explain what do they mean by that. Literally translated stringent would mean regulations, requirements, or conditions . Now is the IAF saying that the T 50 of the RuAF is the end result of below par regulations & requirements ?

Most Indian journalists excel at hyperventilating so they neither have the time nor desire to fully understand technical specifications.

What IAF actually mean by stringent is that the FGFA will have a relatively different flight envelope than the T 50.Simple reason being that the IAF wants the FGFA to be more stealthy ( at the cost of being less manoeuvrable)than it's Russian cousin. Word is that just like the SU 30MKI the EW suite for the FGFA will also be mostly imported from Israel and a part of it will be designed indigenously.

BTW - " I am confident the F-35 will be a good machine"

Maybe our beloved Air Chief & his merry men have not read this

http://s3.documentcloud.org/documents/274217/dod-quick-look-ahern-report.pdf

The latest US DoD report that lists the technical failures of the F 35 . And this is just a partial list. Most of the failures are classified.

Austin wrote:So Indian FGFA demands are more strigent than Russian PAK-FA.

I think the FGFA will be superior to the RuAF PAK-FA

How did you come to that conclusion?
Different=/= superior.

What makes you think Russian AF specifications are any less demanding?

The "original" PAK-FA he talks about is the prototype, not exactly the final product for RuAF.

So Indian FGFA demands are more strigent than Russian PAK-FA.

I think the FGFA will be superior to the RuAF PAK-FA

Not logical...

I know a lot of catholic girls who were brought up very strictly catholic who actually turned out less catholic than some of the girls that weren't even catholic.

Strict demands does not result in quality, it just results in the customer getting exactly what they want.

A good example would be the Su-35BM and Su-30MKI... one meets Indian demands and one does not. You can't say the Su-30MKI is better because it has two seats. The Indian Air Force had a requirement... demand that their aircraft all have two seats to share the work load in a modern multirole fighter bomber. It could be argued that with modern 5th gen avionics the workload is already reduced to a minimum so it can be performed by one crewman.

I would suggest the real reason they are talking about strict demands is because they have already realised they don't want to afford the extra cost of a two seater and in the past they have been clear with their preferences, so by talking about very strict demands they can show they have control despite making a significant compromise to start with.

What I think is that ultimately the new aircraft for India will be best for India and the aircraft for Russia will be best for Russia.

Now is the IAF saying that the T 50 of the RuAF is the end result of below par regulations & requirements ?

No. What it means is they are going to be very specific about exactly what they want and expect to get it. For instance if they had demands for low RCS from all angles then they might require flat engine nozzles despite the effect on manouver capability. The result would likely be higher costs to meet all these demands (which in many cases will result in conflicting solutions that need further solutions to make them all work together).

The "original" PAK-FA he talks about is the prototype, not exactly the final product for RuAF.

Quite true.

By the way, on another note I remember talk of the R-77 being modified with small triangular wings for internal carriage. Now why would they dramatically reduce its manouver capability except if it meant better internal carriage performance?

I suspect the next model R-77s will be specifically for internal carriage and with four launchers in the two main bays on the PAK FA that suggests to me that 4 twin racks would allow 8 missiles of the R-77 new design to be carried in the main bays.

TR1 wrote:How did you come to that conclusion?
Different=/= superior.

Just a thought I recon ( based on open literature )not necessarily value judgement. Anyways, I have explained what "stringent" mean in this context( brand building if you like).

First of all HAL needs to state what will the T 50 be called in India ...FGFA or Perspective Multirole Fighter (PMF). Their latest ( Sept 2011) journal refers to it as PMF . Take a look at the pic below :



According to HAL :

HAL's Aircraft Research & Development Centre (ARDC) has created the flow-through model with 80 components including the dedicated pieces for simulating the deflections of the 12 flight control surfaces of the aircraft.

PMF draws upon the basic structural and system design of the Russian FGFA Technology Demonstrator with modifications to meet IAF specifications which are much more stringent. The broad scope of bilateral cooperation during the joint project covers the design & development of the PMF, its productionization and joint marketing to the third countries. Programme options include the design & development of a twin seater variant and the integration of an advanced engine with higher thrust at a later stage.

So India has very specific requirements and future plans for their aircraft.

The Russians will also have future plans, likely including a carrier based model for after 2020, and I would suspect they will also have in mind other models. Some sort of EW recon model perhaps, and perhaps even a dedicated interceptor model to eventually replace the Mig-31... unless they go the Tu-128 Fiddler way and develop a larger aircraft for the role like a Tu-22M3P or perhaps a PAK DAP.

Over the life time of this aircraft it will most likely get at least a couple of engine changes as well as role changes... by 2030 it might be a drone management aircraft that provides direct line of sight datalinks to attack and fighter drones that enter enemy airspace and do their thing while the PAK FA orbits in international airspace. and controls the mission.

It's quite possible that the RuAF going forward may well place order for the FGFA/ PMF which will carry out the role of a deep penetration aircraft while the T 50 will play the role of the Hunter Killer.

Case in point the decision of the RuAF to induct the Su 30 SM was taken after the Su 35S was inducted in the Air Force.However , realizing the tremendous potential of the export variants SU 30 MKI , SU 30 MKM ,SU 30 MK2 etc the RuAF decided that the Su 30 SM is an aircraft worth having.

If anyone is interested in knowing more about this Russian - Indian project do take a look at this link from Sukhoi

http://www.sukhoi.org/eng/news/company/?form=print&id=3905

The result of higher levels of stealth on the cost of an aircraft both to buy and to operate might make the Russians not want such a final product. I am sure in other areas the collaboration will produce valuable features and systems that they will be happy to put into service, but if they wanted a higher stealth PAK FA they could have gone for that.

Stealth is governed by the laws of diminished returns which is best shown with a non stealthy aircraft.

Take an F-16 and redesign it to make it more stealthy. You could probably spend a few million and fix the biggest problem areas and get a large reduction simply because it was not designed for low observability so there will be plenty of things that can be given small changes that will greatly reduce the RCS.
The problem is that once those easy obvious problems are fixed then you get to the more fundamental problems that are much more expensive to fix and even if you do fix them will only make a small reduction in RCS. Further reductions are either not an option or incredibly expensive and will never make the plane actually stealthy.

That is the reason why the US and now Russia and India and China are making from scratch stealth designs.

The problem is a bit like choosing your aircrafts top speed. Again with the F-16 the designers decided that fighters flying above Mach 2 was actually rather rare so they can make the engine intake simpler and cheaper if they limit the top speed to mach 2. Over the life span of the aircraft they probably saved several million dollars and multiply that by the thousands in service and that is a lot of money saved.

With stealth aircraft you need to pick the aspect and level of RCS reduction... higher or lower will effect both performance and price to buy and operate.

It seems that India wants a higher level than the Russians do, and that is fine, perhaps the Russians know something that the Indians don't or vice versa.

Regarding the Su-30SM I personally think it was more of a case that they were working on the Su-35 which is a single seat aircraft and they realised that a two seater trainer would be useful, but rather than waste money on an Su-35UB, or to follow the new Mig designation system the Su-35D, they chose to order the already in production Su-30SM. I suggest it was more of a case like the Mig-29K2... it was in production so it would save money to order it. Which is not to say either aircraft is bad as such, both are good solid capable aircraft... or they wouldn't be in production.

[quote="GarryB"]

.......................

I suspect the next model R-77s will be specifically for internal carriage and with four launchers in the two main bays on the PAK FA that suggests to me that 4 twin racks would allow 8 missiles of the R-77 new design to be carried in the main bays.

Keypublishing fora and some of the more estimated members there are insisting there will be only two missiles per bay on the T-50. They are quite final about it.

A number of other little features have been discussed there. It seems the general consensus is that the T-50 has its final form already. We are not to expect any kind of changes other than ones dictated by structural strength reasons.

example. No flat nozzles, ever
Only two missiles per bay
Conventional IRST -not like F-35 style-
Two piece canopy
No radar blockers
Rear portion of the engine nacelles will remain circular
Little antennas etc will remain on the aircraft.


Do not assume I am putting down the plane or anything, I simply mention what the discussion seems to point to in other widely used fora.

I thought they mentioned at keypubs by flateric and all that each central bay will carry 3 x R-77 or 2 X R-37M , so total 6 R-77 plus 2 R-73.

Austin wrote:I thought they mentioned at keypubs by flateric and all that each central bay will carry 3 x R-77 or 2 X R-37M , so total 6 R-77 plus 2 R-73.

latest by Flateric is "two per bay, live with it!"

Aegean wrote:

Austin wrote:I thought they mentioned at keypubs by flateric and all that each central bay will carry 3 x R-77 or 2 X R-37M , so total 6 R-77 plus 2 R-73.

latest by Flateric is "two per bay, live with it!"

Perhaps at first. None belives T-50 will be left with only 2 missiles per bay, not the Russians.

Russians tend to arm theirs weapon systems much heavier than rest of the world. Slava class for instance is ship that has in entire

human history had biggest ratio of weapon mass per ship mass.

Same can be said of others. I belive Russians want T-50 in service soon as possible and soon afterwards modernization programs will

follow. Same can be seen on Su-34 upgrade program.

Those bays are huge and wont be left unexploited.

Aegean wrote:

Austin wrote:I thought they mentioned at keypubs by flateric and all that each central bay will carry 3 x R-77 or 2 X R-37M , so total 6 R-77 plus 2 R-73.

latest by Flateric is "two per bay, live with it!"

That is just today though, he himself admitted there is nothing keeping this from changing in future. Certainly bay has enough space for 6 R-77s.

[quote="Aegean"]

GarryB wrote:

.......................

I suspect the next model R-77s will be specifically for internal carriage and with four launchers in the two main bays on the PAK FA that suggests to me that 4 twin racks would allow 8 missiles of the R-77 new design to be carried in the main bays.

Keypublishing fora and some of the more estimated members there are insisting there will be only two missiles per bay on the T-50. They are quite final about it.

A number of other little features have been discussed there. It seems the general consensus is that the T-50 has its final form already. We are not to expect any kind of changes other than ones dictated by structural strength reasons.

example. No flat nozzles, ever
Only two missiles per bay
Conventional IRST -not like F-35 style-
Two piece canopy
No radar blockers
Rear portion of the engine nacelles will remain circular
Little antennas etc will remain on the aircraft.


Do not assume I am putting down the plane or anything, I simply mention what the discussion seems to point to in other widely used fora.

I am sorry, but this is not even vaguely accurate.
There WILL be radar blockers, fact.
Who said there not be flat engines, ever? The certainty you are implying is not even remotely true.
Two missiles for bay is the current configuration. What basis is there the final product won't increase it?
What does conventional IRST mean? The IRST will be distributed, fact. Also there is nothing magic about F_35s faceted IRST.
Engine nacelles being circular was clear from start, but that is not stealth preventing in any way.
Little antennas? You think Russian designers are so stupid about stealth? There are little antennas and protrusions on F-35 too.
The skin and RAM has not even been fitted on the PAK-FA yet!

I am a regular posted on Key Pub, and I find your assetions hard to back up on the forum.
"General consensus" on other forums is meaningless, since it is people with no actual knowledge of the program.

[quote="TR1"]

Aegean wrote:

GarryB wrote:

.......................

I suspect the next model R-77s will be specifically for internal carriage and with four launchers in the two main bays on the PAK FA that suggests to me that 4 twin racks would allow 8 missiles of the R-77 new design to be carried in the main bays.

Keypublishing fora and some of the more estimated members there are insisting there will be only two missiles per bay on the T-50. They are quite final about it.

A number of other little features have been discussed there. It seems the general consensus is that the T-50 has its final form already. We are not to expect any kind of changes other than ones dictated by structural strength reasons.

example. No flat nozzles, ever
Only two missiles per bay
Conventional IRST -not like F-35 style-
Two piece canopy
No radar blockers
Rear portion of the engine nacelles will remain circular
Little antennas etc will remain on the aircraft.


Do not assume I am putting down the plane or anything, I simply mention what the discussion seems to point to in other widely used fora.

I am sorry, but this is not even vaguely accurate.
There WILL be radar blockers, fact.
Who said there not be flat engines, ever? The certainty you are implying is not even remotely true.
Two missiles for bay is the current configuration. What basis is there the final product won't increase it?
What does conventional IRST mean? The IRST will be distributed, fact. Also there is nothing magic about F_35s faceted IRST.
Engine nacelles being circular was clear from start, but that is not stealth preventing in any way.
Little antennas? You think Russian designers are so stupid about stealth? There are little antennas and protrusions on F-35 too.
The skin and RAM has not even been fitted on the PAK-FA yet!

I am a regular posted on Key Pub, and I find your assetions hard to back up on the forum.
"General consensus" on other forums is meaningless, since it is people with no actual knowledge of the program.

Fair enough.

I read the other forum quite regularly. I am not a poster there though, as I always thought there are some russian (?) members with direct access (?) to good information.

What I have gathered so far is what I have listed above.

There is no indication of a radar blocker in the works, nor is there on in the schematics in the pattern documents. There were some people talking about it, but nothing coming from the "knowledgeable" members.

The debate on the missile bays has been dragging on for long, until flateric said, that it is only two per bay. He is respected enough, so I believe him. Of course there is nothing preventing designers to change that in the future, I am just saying what the current design is. Following the same reasoning the F-22 could/would/should have an IRST in the near future.

What I mean with conventional, is simply referring to the functionality of the system in F-35 as opposed to the functionality on the T-50. Not the shape of the thing. I know there are placements for extra sensors on the T-50. Their placement however makes a similar type functionality hard. I am not saying every plane should have the same functionality. It is just that a lot of people hoped for that. I am just stating what seems to be the case so far.

There are not going to be any flat nozzles. Besides that tragic looking flat nozzle tested on an Su-27, there have been no other news on that coming from russia. And the plane is touted to have 3D TVC which bar a late engineering miracle, precludes flat nozzles.

The two piece canopy has been the topic of debate for many. It seems benefit or no benefits, this is the intended design.

There is a single antenna on the F-35. No conventional tubes etc. I expect to see them reduced on the production T-50, but not gone.

Rear portion of the engine nacelles being circular means that one has a potential are of diminished LO characteristics on the aircraft, add to that the nozzles and one has quite some contributors on the craft. A curious choice since a different shape would not have been difficult to manufacture, even as a shroud to the existing ones. I have heard about the miracles the ITAE performed on the Su-35 and its RCS, but I think it is a bit fetched to think that RAM alone will make the rear section "LO" !


I don't know how vaguely accurate I have been, but I have seen no hints of evidence to suggest otherwise.

I would also like to add to that a difference I noticed between US built planes and Russian / chinese planes. The leading edge slats on both the F-22/F-35 extend all the way to the tip of the wing thus avoiding a "tooth" shape just before the wingtip.

Neither the T-50, and the J-20 have this, creating a potential scattering point. I don't advocate that the americans know everything, but I am just noticing that they take no chances. It seems the opposite with Russian/chinese designs, were canards and non edge alignment and various other choices seem to indicate a non so much attention to detail.

The T-50 program moves along at an excellent pace so far, which suggests to me that the plane is exactly as it was meant to be. Everything else is I think wishful thinking at this stage.

Personally (and it is just my worthless opinion) the only thing I expect to change on the T-50 is the new more powerful (but still conventional nozzled) engines.

Flateric only posts small bits and pieces on the Keys forum. There's more info from him and others involved in the aviation industry on the Russian language Paralay forum.

The F-22/35 are in many respects 1980's designs with solutions from that era. The Pak Fa has some different features which weren't practical at the time...for example the air intakes. Flateric described the Pak Fa's as a technological masterpiece.

And I really hope the Russian's don't go for flat nozzles....it's a inefficient way to reduce the IR signature

Keypublishing fora and some of the more estimated members there are insisting there will be only two missiles per bay on the T-50. They are quite final about it.

So they have decided based on the first four flying prototypes... how very closed minded of them.

A number of other little features have been discussed there. It seems the general consensus is that the T-50 has its final form already. We are not to expect any kind of changes other than ones dictated by structural strength reasons.

So it is going into service with no functional IRST? Again, very interesting.

example. No flat nozzles, ever
Only two missiles per bay
Conventional IRST -not like F-35 style-
Two piece canopy
No radar blockers
Rear portion of the engine nacelles will remain circular
Little antennas etc will remain on the aircraft.

Do they not understand the concept of prototype?

The 4th flying prototype is the first model to actually have a radar fitted and they have the design sealed in concrete?

You just need to look at the difference between the Su-27M and the Su-35BM to show what Sukhoi had learned on its own and also through cooperation with India (and therefore also companies like Thales of France and Israeli companies with all the foreign gear they integrated into the Su-30MKI). They haven't even started working on the PAK FA-MKI yet and the esteemed members at Keypub have decided it has developed as far as it can go.

BTW flat nozzles are great for reducing RCS and mixing cold air into the engine thrust to reduce IR signature, but at a cost of a significant amount of thrust and also at the cost of 3D thrust vectoring capability. The Russians have shown flat nozzles before and rejected them in the past as not suitable.

Regarding the canopy framing... anyone who has sat in a real cockpit knows you don't turn left and right with a fixed head position in a real plane... you can move your head forward a little to see anything hiding beneath the framing and that forward and back movement becomes a natural part of looking for things... just like knowledge that your rear view mirror in your car has blind spots so before you change lanes you physically look for things in your blind spot before you start to change lanes or turn.

The purpose of the framing is visibility... the front portion of the canopy needs to be thick enough to withstand impacts from birds etc. If you have a one piece canopy that means you have two choices... one is make it all thick which actually reduces visibility because looking up and sideways and back the canopy is much thicker than it needs to be. The other solution is to make it thicker at the front than the top, sides and rear, which makes it easier to see but introduces distortion in the areas of transition.

latest by Flateric is "two per bay, live with it!"

Which raises the question why would they be revising the design of the R-77 to small triangular fins, unless it allowed more missiles to be carried.

There are two weapon positions in each bay, but there are also two weapon pylons underneath an Su-35BM, yet models have been shown that have twin launchers for R-77 missiles that eject the missile downwards on launch. If the Su-35 can have 4 R-77s on its two belly pylons then why wouldn't the PAK FA have 4 R-77s in each bay?

I would expect their new 9M100 short range AAMs will be 4 to a weapon bay at the very least... depending on how long they are.

Who said there not be flat engines, ever? The certainty you are implying is not even remotely true.

From what I have read in articles quoting people actually involved in the program they have said that they will look at flat nozzles but have not decided whether they will make it to the final aircraft.

Personally I suspect the Indians will want flat nozzles so they will be developed for FFGA, and with a bit of money and time and brains they might solve some fundamental problems that are keeping the Russians from adopting that solution. Of course they might not, and India might accept a less manouverable aircraft that is more stealthy as a conscious choice.

Two missiles for bay is the current configuration. What basis is there the final product won't increase it?

More accurately two missile hard points per bay... the Mi-28 carries 16 ATAKA missiles mounted on two missile hard points. The two hardpoints are designed to carry RVV-BD missiles or heavy air to ground weapons, so they should have plenty of capacity for multiple weapon adapters. The key problem at the moment is the design of the medium and short range missiles makes fitting multiple weapons a challenge, but they have been working on new custom designed missiles for some time... and I don't think they will make them R-27s with huge butterfly wings... they will be optimised for the weapon bay of the PAK FA. This suggests to me that with two weapon pylons that in actual fact there will be 4 R-77Ms in each weapon bay for a total of 8 missiles.

What does conventional IRST mean? The IRST will be distributed, fact. Also there is nothing magic about F_35s faceted IRST.

Exactly... what is all this crap about curves not being stealthy?

The F-117 didn't have curves but the F-22 and B-2 clearly do. The difference is processing power of the computers used to design the different aircraft and also the tooling in the factories making the aircraft being able to make them to the accuracy needed.

There is no indication of a radar blocker in the works, nor is there on in the schematics in the pattern documents. There were some people talking about it, but nothing coming from the "knowledgeable" members.

The Mig-29 had the worlds best radar blocker for its engine... it was a solid sheet of metal that completely closed off the front of the intake so no radar energy could enter from the front.

The Flanker equivalent had a mesh door with the same purpose and function, while the NK-32 engine of the Tu-160 Blackjack has the front fan blades coated with radar absorbent material which makes radar blockers in the intake even less necessary.

BTW I have read a few articles from Russian sources that look at different radar blocking mechanisms.

Following the same reasoning the F-22 could/would/should have an IRST in the near future.

They don't even have helmet mounted sights and AIM-9X missiles, why bother with IRST?

There are not going to be any flat nozzles. Besides that tragic looking flat nozzle tested on an Su-27, there have been no other news on that coming from russia. And the plane is touted to have 3D TVC which bar a late engineering miracle, precludes flat nozzles.

And before January last year there were no photos of the PAK FA so I guess that didn't exist either?

I have heard about the miracles the ITAE performed on the Su-35 and its RCS, but I think it is a bit fetched to think that RAM alone will make the rear section "LO" !

So if flat surfaces is the only way to make something LO can you explain why the F-22 and B-2 and F-35 don't look like the F-117?

I would also like to add to that a difference I noticed between US built planes and Russian / chinese planes. The leading edge slats on both the F-22/F-35 extend all the way to the tip of the wing thus avoiding a "tooth" shape just before the wingtip.

And what difference does that make in your expert opinion?

The dogtooth in the horizontal tail surface on the F-15 is actually on purpose and improves performance by acting like a vortex generator... the modern equivalent of a wing fence to prevent span wise flow ruining the lift generated near the wing tip.

The enormous dogtooth hooks on the Mig-23 with the wings fully swept resulted in vortexes that allowed a much greater angle of sweep which further reduced drag and buffet at low level and allowed it to fly much much faster at low and high altitudes, while still retaining good manouver capability.

Neither the T-50, and the J-20 have this, creating a potential scattering point. I don't advocate that the americans know everything, but I am just noticing that they take no chances. It seems the opposite with Russian/chinese designs, were canards and non edge alignment and various other choices seem to indicate a non so much attention to detail.

It is a prototype. The radar cross section is not important on prototypes... whether it flys or not, whether the radar works, whether the weapons release properly from the weapons bay or not, whether the navigation system works are all things you test and check in a prototype.

There will be a RCS prototype but it will be in a building on a stick with radar antenna pointed at it while it spins around.

There is no point is making the rear LO when they haven't even got the engine that it will be flying with ready yet.

Personally (and it is just my worthless opinion) the only thing I expect to change on the T-50 is the new more powerful (but still conventional nozzled) engines.

Actually the next thing will likely be weapons tests on the 5th prototype, while the earlier prototypes will be testing avionics and the flight envelope. They will likely be testing the self defence suite as that often takes a lot of time too.

Aegean wrote:



There is no indication of a radar blocker in the works, nor is there on in the schematics in the pattern documents. There were some people talking about it, but nothing coming from the "knowledgeable" members.

Not sure how you got this- there is plenty of insider info that a radar blocker is in the works. There was barely any detail about PAK-FA before it was revealed, remember? Doesn't mean it did not exist, same with radar blockers. It is clear the engine faces will not be left like that, that would be absurd, given that Sukhoi has worked the S-duct solution before.

The debate on the missile bays has been dragging on for long, until flateric said, that it is only two per bay. He is respected enough, so I believe him. Of course there is nothing preventing designers to change that in the future, I am just saying what the current design is. Following the same reasoning the F-22 could/would/should have an IRST in the near future.

Right, but what is the plane today? Compare it to F-35/F-22 prototypes. Remember how rough it looked? As of today, yes there are only 2 launchers in each bay. The plane is not nearly in service though, so it is fair to speculate 6 could be fitted. The whole thing maybe a moot point, if the plane carries RVV-BV sized missiles, as there is no way anyone can fit 6 of those big boys in the bay. Not to mention the Kh-58UKShK solution is more impressive than anything the F-22 has internally.

What I mean with conventional, is simply referring to the functionality of the system in F-35 as opposed to the functionality on the T-50. Not the shape of the thing. I know there are placements for extra sensors on the T-50. Their placement however makes a similar type functionality hard. I am not saying every plane should have the same functionality. It is just that a lot of people hoped for that. I am just stating what seems to be the case so far.
Potentially true- however the IRST on the T-50 is far more than the one on Su-27. So I don't see how it is conventional. Will it have the same ground attack utility than the F-35 has? I don't know, but the planes have different purposes after all. It would be a bit much to expect the PAK-FA to have everything the F-22 has, the F-35 has, and more.

There are not going to be any flat nozzles. Besides that tragic looking flat nozzle tested on an Su-27, there have been no other news on that coming from russia. And the plane is touted to have 3D TVC which bar a late engineering miracle, precludes flat nozzles.

It is a fact that the nozzles are not final. You can bet the final nozzles will have RCS and IR reduction in mind. The No news argument holds no water. Not to mention, there HAVE been news and patents by engine manufacturers regarding Flat Nozzle work.

There is a single antenna on the F-35. No conventional tubes etc. I expect to see them reduced on the production T-50, but not gone.

Based on what? Look @ X-35, YF-22. They had terrible surface finish and lots of protrusions. I don't see any reason why PAK-FA won't have smooth body. Also, I can find you many protrusions on the F-35, if not outright tubes.

Rear portion of the engine nacelles being circular means that one has a potential are of diminished LO characteristics on the aircraft,

Not true. A sphere has a uniform, low RCS signature if properly treated. Angles work better in some arcs, but are significantly worse in others. I can find many spherical parts of the F-35 - just look at the underbody! Many bulges because they could not fit the stuff in a uniform body. That is somehow better than PAK-FAs nacelles?

add to that the nozzles and one has quite some contributors on the craft. A curious choice since a different shape would not have been difficult to manufacture, even as a shroud to the existing ones.
Right, so lets give thr Sukhoi guys some benefit of the doubt here? They know what they are doing, Russia has RCS test ranges.

I would also like to add to that a difference I noticed between US built planes and Russian / chinese planes. The leading edge slats on both the F-22/F-35 extend all the way to the tip of the wing thus avoiding a "tooth" shape just before the wingtip.

Neither the T-50, and the J-20 have this, creating a potential scattering point.

The T-50s slats are as flat as any American planes. Don't let photos of them deployed confuse you

The T-50 program moves along at excellent pace so far, which suggests to me that the plane is exactly as it was meant to be. Everything else is I think wishful thinking at this stage.

The program is years away from serial production, so I wouldn't be so quick to assume.

10 characters.

Cyberspec wrote:Flateric only posts small bits and pieces on the Keys forum. There's more info from him and others involved in the aviation industry on the Russian language Paralay forum.

The F-22/35 are in many respects 1980's designs with solutions from that era. The Pak Fa has some different features which weren't practical at the time...for example the air intakes. Flateric described the Pak Fa's as a technological masterpiece.

And I really hope the Russian's don't go for flat nozzles....it's a inefficient way to reduce the IR signature

The PAK-FAs intakes are a LOT more interesting than the Raptors, for example.
There are 8 (!!) angles making up the inlets, that isn't there randomly.

I will re-iterate: look @ prototype X-35 and YF-22, before assuming PAK-FA stealth on the current AERODYNAMIC and SENSOR testbeds.

TR1 wrote:.

This is the F-35, notice the leading edge slats.

No look at the leading edge of the F-22 wings



Now look at the T-50




I think we are talking about different things. I am puzzled as to why the US jets have eliminated the outboard dog tooth by having this smooth leading edge and Sukhoi hasn't.

It is definitely an irregularity and a potential -if not certain- contributor to RCS.

It has been pointed out, that I should have faith in Sukhoi for they know what they are doing.
I never said they didn't. I am saying the plane looks exactly like they wanted. What I am thinking are the reasons that made them make the plane like this.

When it comes to the IRST, the one on the F-35 augments the situational awareness of the pilot in a number of ways. Apparently the one on the T-50 is used exactly like the ones on the previous Sukhois, it is just ..better in performance.

I understand defending the T-50. It is fine by me. I don't attack it per se. I am just pointing out things.

You say the plane has a long way to go. I believe you. Also I believe the statements that say that IOC planes will be flying around 2016. At this rate, it is a high possibility.

I personally don't subscribe to the reasoning of "they know best" . .of course they do, a crude example however is the car industry, all manufacturers know what they are doing, and their cars are all excellent since they adhere to strict regulations. However amongst all these excellent cars, some are standing out. For various reasons.

Obviously the T-50 is the most innovative plane -in terms of design- we have seen so far, but that means only so much these days. If it is not coupled with capable systems, and the ability to level the playing field in the LO department, it won't mean much.

that is why a series of choices made by the design team makes me wonder.

my 2c

I am not sure what you mean - do you mean the slats, which seem as flush on the PAK-FA when in neutral position as any US plane, or the LERX?

http://farm1.staticflickr.com/189/509895325_66b4b92f5f_z.jpg?zz=1

http://www.profimedia.si/photo/condensation-forms-on-the-leading-edge-of/profimedia-0030437355.jpg

As you can see, there are gaps when the slats are actually deployed.

EDIT: Gotcha, edge of the slats @ the end of the wing. Not sure, but I am also not sure about the actual RCS effect, and if it is negative.
Slats are only used @ high angles of attack anyways, so it's not like they will be used for aircraft correction in a BVR encounter at altitude.

I don't see how the IRST on the T-50 is exactly the same as the one on Su-27s. It is clear the PAK-FAs is far more capable, and also distributed throughout the plane. That by definition will asist pilot awareness, and track targets all around the plane.
What does the F-35s DAS offer that is so revolutionary? The one advantage that I see on it is ground attack performance, but that is a result of F-35 being an A2G platform.

This is what DAS does, according to manufacturer:
The DAS provides:

Missile detection and tracking
Launch point detection
Situational awareness IRST & cueing
Weapons support
Day/night navigation

PAK-FA makes provisions for all of that with its optical systems, so I don't see the problem.
There are also a bunch of silly claims about DAS tracking a rocket- big accomplishment, tracking one of the bigest IR sources ever.
Early AAMs locked on to the sun as well - talk about range!

It is definitely an irregularity and a potential -if not certain- contributor to RCS.

How do you work that out?

The piece that doesn't move remains edge on to a radar in the forward quarter. To get a corner reflector type return from the piece that doesn't move you would need to be viewing it from the opposite side of the aircraft, which means the fuselage of the aircraft would be in the way.

Aerodynamically it would generate a vortex and therefore act as like a wing fence near the wingtip, which would greatly reduce spanwise airflow and therefore actually greatly reduce the wingtip vortex which reduces drag.

When it comes to the IRST, the one on the F-35 augments the situational awareness of the pilot in a number of ways. Apparently the one on the T-50 is used exactly like the ones on the previous Sukhois, it is just ..better in performance.

Rubbish. The new IRST system on the PAK FA includes dozens of optical sensors distributed all round the aircraft and perform all the same functions that the much vaunted DAS system on the F-35 does. They also have similar systems for the Mig-35 and Su-35BM, so in a sense it is the same as the system fitted on the Flankers assuming that the Flanker you are referring to is the Su-35BM.

Obviously the T-50 is the most innovative plane -in terms of design- we have seen so far, but that means only so much these days. If it is not coupled with capable systems, and the ability to level the playing field in the LO department, it won't mean much.

that is why a series of choices made by the design team makes me wonder.

You need to keep in mind that the PAK FA is not an F-22ski or F-35ski... Russia doesn't need an aircraft that will allow it to invade a foreign country and shoot down all its planes and then start to take its air defence network to pieces.

If that were the case it wouldn't need IRST, or L band wing mounted radar.

Its real job is to deal with high flying F-22s and low flying F-35s, but it is not alone and will be working with S-400 and Vityax air defence SAMs.

The PAK FA doesn't need super stealth to fly into the centre of the US, it needs enough stealth to render AMRAAM useless so it becomes a knife fight... because it is designed for manouver performance and agility and it is designed to win that knife fight.

The F-22 is a stand off sniper that kills at long range, but its primary weapon needs a radar return to get a lock and to guide it, so against 3rd world countries with hundreds of Mig-29s and Su-27s it has the advantage of being able to see but not be seen.

Against a group of Su-35BMs with L band AESAs and also Pak Fas that it can't detect so easily, all of a sudden it wont be able to zip around at mach 1.4 at high altitude and shooting everything it sees at long range because of the advantage of altitude and speed extend the reach of its AMRAAMs... because at that speed it will have a significant IR signature that is going to make it stand out in IRSTs on Su-35BMs and PAK FAs. The size of the RVV-BM should allow a rather large radar to be fitted which should maximise its ability to detect stealthy targets. There is likely to be an IIR guided version too which would be ideal and whose kinetic range would cancel out any advantage the F-22 might get from a supercruise launch position... of course the Su-35BM has plenty of fuel and could climb and accelerate to higher speeds to get the same extra reach for its missiles too.

The combination of stealth and a variety of sensors with the PAK FA and the missile payload of the Su-35BM they should actually be rather well protected from NATO attack for the foreseeable future.

GarryB wrote:

It is definitely an irregularity and a potential -if not certain- contributor to RCS.

How do you work that out?

The piece that doesn't move remains edge on to a radar in the forward quarter. To get a corner reflector type return from the piece that doesn't move you would need to be viewing it from the opposite side of the aircraft, which means the fuselage of the aircraft would be in the way.

Aerodynamically it would generate a vortex and therefore act as like a wing fence near the wingtip, which would greatly reduce spanwise airflow and therefore actually greatly reduce the wingtip vortex which reduces drag.

I know this because it is standard radar theory. Irregularities or discontinuities on the body under radiation, induce scattering points. Any discontinuities. Same reason panels are supposed to be sawtoothed is to eliminate this.

I am inclined to ask why you think the vortices will be what the designers wanted? It is as much an assumption as it is mine. The F-22 and the T-50 have very similar wings, why would one need the vortex fence and the other not?

Besides the slats are I think extended even in level flight. All the photographs I have seen of the T-50 at level flight show them used. Perhaps I am wrong.


The IRST sensor at the front of the plane is the primary sensor, yes ? the secondary sensors scattered around the plane cannot have the same performance. A simple enough deduction.

The F-35 has its primary sensors placed in such a way as to provide that 360 field of view.

The sensor at the front of the T-50 has what 60+- degrees off centerline ? maybe more, I don't know.

One person on youtube said that the F-22 is more agile than the T-50 because it has larger rudders and that 3D thrust vectoring only makes a tiny difference in maneuverability compared to 2D