The stealth capabilities of the T-50 PAK FA

[Hummingbird]

Arent pictures of the F-18Es intake prohibited by the Military?

 

Coulda sworn personel were not allowed to take pictures of the SHs intake, let alone post online.

 

I don't think so considering how many detailed pictures that are floating around. I'm thinking the real secret is the composition of the blocker and not so much the shape.

[Krippz]

Arent pictures of the F-18Es intake prohibited by the Military?

 

Coulda sworn personel were not allowed to take pictures of the SHs intake, let alone post online.

 

Doubtful, the pictures are widely available online.

[SkateZilla]

Just because they are all over google search doesnt mean its allowed.

 

Im confident that such pictures are prohibited, waiting for my sources to get back to me, but I was told that Personel were prohibited of taking pictures of the SuperBugs Intake Features.

[King_Hrothgar]

To me Pakfa is still more of a 4.5Gen than 5Gen. It seems on par with the likes of Eurofighter and Rafale.

 

The entire generation thing is a bit arbitrary anyways. I think when all is said and done, 5th generation will ultimately be defined as fully digital and reprogrammable systems combined with sensor fusion rather than all aspect stealth against X-band radar. The all aspect stealth bit is shaping up to be an oddity, much like the MiG-25's mach 3 speed is for 3rd gen jet fighters. Under that definition, I'm not sure the F-22 actually makes the 5th gen fighter cut, it might only be 4.5 gen. Regardless, it's an arbitrary term. What matters is how it performs against opponents of the same vintage. I suspect the PAK FA will be near the top of the food chain assuming it ever starts rolling of the assembly line.

 

In regards to pictures, it's a fanblade. They all kinda look the same. The only thing secret about something like that is what it's made of (maybe) and possibly how it is made. A picture doesn't tell anyone anything of value for an object like that. Obviously that doesn't mean there aren't any rules against it. It just means it doesn't actually give away any actual secrets.

[SkateZilla]

In regards to 4.5 / 5 Gen..

 

I dont think there's a set criteria.

 

Gen 5 is usually attached to the new Stealth Fighters (F-22, F-35ABC, PAK-FA/T-50/J-20 etc), while 4/4.5 is attached to Conventional Fighters (F-18EFG, Su27,33,34,35, Mig29, etc etc)

 

Funny part is though, F-22 is built w/ 80s tech, and is already had production lines shut down,

and if there's a minuscule chance they re-open them the F-22B or whatever they call it wont be the same as the F-22A, the 80s Tech will be replaced with Current Systems / Tech and Un-Needed Bulk will be cut from the design.

 

 

As for the Picture, if it is indeed prohibited as I think it is, It will be deleted from forums, this isn't a no rules blog, if it's prohibited, its prohibited, the same goes for posting anything classified, etc

Edited March 11, 2016 by SkateZilla

[Hummingbird]

Just because they are all over google search doesnt mean its allowed.

 

Im confident that such pictures are prohibited, waiting for my sources to get back to me, but I was told that Personel were prohibited of taking pictures of the SuperBugs Intake Features.

 

What about at airshows then? I seem to remember seeing them there as well, there were two Superbugs sitting on the ground at the Roskilde airshow last summer which I attended - don't remember any intakr cover as I walked past. So I can't imagine it being a problem.

Edited March 11, 2016 by Hummingbird

[SkateZilla]

What about at airshows then? I seem to remember seeing them there as well, there were two Superbugs sitting on the ground at the Roskilde airshow last summer which I attended - don't remember any intakr cover as I walked past. So I can't imagine it being a problem.

 

The Rule may have changed, which is why I reached out to a few friends here at NAS Oceana for clarification.

[SkateZilla]

Confirmed, Pictures of F-18E/F/G Inlet Devices are still not allowed.

 

As such, post w/ photo deleted.

Edited March 11, 2016 by SkateZilla

[NOLA]

3.

A) What is the purpose of goint to flight test, if whatever characteristics you get won't represent the real result?

B) What is the purpose of radar blocker, if you have intake ramp in front of it?

 

A) Uhhhh. Because they don't test *everything* on the first frame at once? Isnt that obvious? There are a gazzilion things the later frames have that T-50-1 doesnt have. T-50-1 by no means represent the final aircraft or "real result". Radar blocker is very very far down on the list of important things to test on first prototypes.

 

B) No idea what you mean. Radar blocker and intake ramp doesnt cancel each other out.

 

Yeah, that picture in the OP looks like a blocker not the fan itself.

 

No. Again, there is no blocker on T-50-1. It is fantastically easy to compare the number of the "vanes" we seen in the infamous picture and compare to izd.117/117S IGV's.

 

That's the first stage of low pressure compressor.

 

Not entirely correct. What we see is the is IGV first, low pressure vanes are behind that.

[ФрогФут]

A) Uhhhh. Because they don't test *everything* on the first frame at once? Isnt that obvious?

It affects engine operation, it affects acceleration, cruise speed and other flight characteristics. And they are already in army tests. And anyway RB is one of the factors, that makes SH accelerate, like a brick.

No idea what you mean. Radar blocker and intake ramp doesnt cancel each other out.

Ramp itself has sharp edges, which increase RCS.

Edited March 12, 2016 by ФрогФут

[NOLA]

There are one million other things that affect all the things you have mentioned that are not tested on T-50-1 either. None of the 5 radars, no EW, no sensors, no RAM, no FOD clamshells in the intakes, very limited G's, inability to use any weapons etc etc. They have also been through several sets and probably subversions of izd.117 on the frames - which obviously effect all the things you have listed. Again, radar blocker is the absolute least of the concerns. I am pretty sure it isnt fitted on atleast the first three frames - but i cant claim it hasnt been fitted to *any* frame yet. It wouldnt surprise me at all.

 

As to the ramp, i am sure they (Sukhoi) are aware of any effect it has on RCS. If you are suggesting T-50 will only have ramp and no radar blocker then you are being silly.

[ФрогФут]

Ok, ok, calm down, you are of course right.

[OneBlueSky]

Like others posted, it's really hard to know what it "will be" from publicly demonstrated prototypes. Much like the US or anyone else, when it comes to important things, it probably won't show up at airshows or easily spotted areas for flight testing like the G limited, radar-less etc. prototype does.

 

I am also not sure how slippery to radar they intend for it to be when it finally comes into service. From my understanding it was intended to be a combination of stealthy, maneuverable, and affordable. There are several improvements already mentioned that could improve it's stealth ability, and who knows what it will end up as. The whole world knows what could be done, I am sure they are well aware themselves. And it's not necessarily a bad approach. The F-22 and F-35 are massively expensive and offer few if any real world gains for the money over their active duty counterparts effectively making them a complete waste. Which is why they get so much controversy surrounding them. I doubt if they'll ever be used against superpowers that could reasonably be a threat large enough warranting them, and let's face it... The nations they'll be deployed against could just as easily be beaten by a handful of older US birds. Russia may have taken this financial mistake/disaster into account because these were two massive ones.

 

For the engines though, Russians have used S-Intakes in the past as NOLA said, and there's very good reason they don't use them again, and other solutions exist to avoid RCS from the engines. (Better ones, arguably). They didn't forget or make a mistake in design, they've tried it, they know why it's a bad idea and elected to not use it.

Edited March 13, 2016 by OneBlueSky

[garrya]

u

y[/b]' date=' maneuverable, and affordable. .[/quote']

 

All 3? , highly unlikely

I think it gonna massively expensive like the F-35, F-22

[BronzeBuddha]

 

That's the diagram of the PAK FA radar blocker cross section leaked by an insider a few years ago. Allegedly that's just one section of the blocker, and the entire blocker (at the time of the drawing leak) is supposedly about as long as the diameter of the engine.

 

Radar blockers aren't even unique to the PAK FA. The F-18E/F has them and the F-22 has ceramic RAM blockers right before the nozzles to help with near quarter stealth.

 

[SkinnyCyclist]

Yes, they really need to remove the ladder before take-off.

[franciwzm]

R pak fa rcs (frontal)

 

Initially sukhoy claimed an rcs between 0,1 ad 0,4 square metres; now is much more vague and claim an rcs between 0,1 and 1 square metres; many sources (and indians as well) claim a frontal rcs of not less then 0,5 m2 if the plane will be properly assembled with flat-head rivets for example...

http://errymath.blogspot.com/2015/06/sukhoi-t-50-pakfa-stealth-technology.html

 

http://www.realcleardefense.com/articles/2015/11/05/the_f-35_vs_the_russian_su-35_and_the_pak_fa_108649.html

 

Just in comparison official frontal rcs of eurocanards is 0,1 clean, 0,3-0,4 in air to air configuration, 0,8-0,9 with 2 external tanks and full air to ground weapons...Pak fa with external weapons will be likely massively larger then eurocanards one...

 

I would consider also that back rcs of pak fa will be considerably larger of eurocanrds for example, and IR signature will be massive...Typhoon IRST can detect an F16 sized thermal signature 90km+ away; it is likely that pak fa signature will be no less then su35 one, not beeing evident any themal signature conceling tecnique even in basic design (150km+ ? )

Edited May 12, 2016 by franciwzm

[Weta43]

sukhoy claimed an rcs between 0,1 ad 0,4 .... many sources (and indians as well) claim (more correctly "Guess" for their own purposes) a frontal rcs of not less then 0,5 m2

 

official frontal rcs of eurocanards is 0,1 clean, 0,3-0,4 in air to air configuration

 

Clean doesn't really count for much though - it's not a combat aircraft if it has no weapons :-) . So given that the PAK-FA has longer legs and 6 internal weapons bays, carrying 4*BVR, 2*WVR would make its combat RCS about the same as the 'Eurocanard' with a 'stealthy' A2A load 4*AIM-120 2*AIM-9, and about half that of a 'Eurocanard' with tanks & weapons on in a combat patrol configuration.

 

Pak fa with external weapons will be likely massively larger then eurocanards one

 

But as above, the PAK-FA can perform multi-role duties while carrying all weapons internally & so without increasing its RCS, while the 'Eurocanard''s RCS blossoms as soon as you give it legs or arms to (your numbers) 0.9 m^2...

 

it is likely that pak fa signature will be no less then su35 one, not beeing evident any themal signature conceling tecnique even in basic design

Where did this analysis come from ?

[franciwzm]

Hello there ; thank you for your interest in my post;

 

R" and about half that of a 'Eurocanard' with tanks & weapons on in a combat patrol configuration." Not really: how much gonna be pak fa rcs with full or at least comparable air to ground mission ? We dont know, likely much more then eurocanards, beacuse external weapons dont add rcs linearly to any stealth design but incrementally, and considering pak fa is larger then su35 then is larger then F15

 

R "So given that the PAK-FA has longer legs and 6 internal weapons bays, carrying 4*BVR, 2*WVR would make its combat RCS about the same as the 'Eurocanard' with a 'stealthy' A2A load 4*AIM-120 2*AIM-9"

 

It depends : typhoon has semi recessed air to air missiles positions, which are designed to operate not only with amraam , but much more important with meteor missile; we know thata R77 is considerably larger and heavier then amraam, and 20% shorter engagement range then amram C and much less then amraam D, : so even if a longer range missile then R73 will be developed for air to air combat vs fighter sized and manouvring boogies, kinda obvious will not fit internally; so a typhhon with 4 meteors and 2 IRIS-T (which main purpose is defensive one beeing capable to intercept agile wvr missiles and low rcs cruise missiles) has not same strategic configuration then a PAk-fa with 4 R73 and 2 R77

 

R " it is likely that pak fa signature will be no less then su35 one, not beeing evident any themal signature conceling tecnique even in basic design

Where did this analysis come from ?"

 

..In every forum I keep reading beeing the main flaw of basic design of pak -fa : there is no sign of low observable (LO) exhaust nozzle design, not speaking of or thermal tiles and recessed engines such as in f22 or B2 ("platypus" shaped exhaust: 1/4 of cost of B2 maintenance are thermal tiles covering exhaust surfaces) , but lets keep it simple : neither a petal exhaust design is observable such as in F15E, superhornet or eurocanards; put all this in the bigger an larger fighter ever designed (pak fa), not considerably possible to use an high bypass ratio engine like in A10 because it is very inefficient at high quotes, consider that current su35 engine consumes exactly 3 times more fuel then the most efficient fighter engine , the EJ200 of eurofighter, and you can suspect that thermal signature of pak fa will be at leats as big then one in su35, : thermal signature of su35 is much bigger then eurocanrds one, due in part to sheer size and weight of fighter, in part to low efficiency of engine...Not considering airfram friction, basis engine thermal signature of AL-41F looks massive in this comparison https://defenseissues.wordpress.com/2014/12/06/fighter-aircraft-engine-comparision/

 

Flying pak fa protoypes show exhausts with no visible petals, furthermore exhaust positions is not recessed but at the opposite prominent/extruded such as in su-35 : it does not make much sense to design a LO fighter if you take no apparent thermal signature reduction tecniques, expecially in a very large and heavy fighter ,considering that most advanced IRST, such as thyphoon pirate, can track an f16 trough IRST from not less then 90km ( An su35 thermal signature is on average 2 to 3 times larger the an F16 one. )

Edited May 13, 2016 by franciwzm

[Pilotasso]

Clean doesn't really count for much though - it's not a combat aircraft if it has no weapons :-) . So given that the PAK-FA has longer legs and 6 internal weapons bays, carrying 4*BVR, 2*WVR would make its combat RCS about the same as the 'Eurocanard' with a 'stealthy' A2A load 4*AIM-120 2*AIM-9, and about half that of a 'Eurocanard' with tanks & weapons on in a combat patrol configuration.

 

 

 

But as above, the PAK-FA can perform multi-role duties while carrying all weapons internally & so without increasing its RCS, while the 'Eurocanard''s RCS blossoms as soon as you give it legs or arms to (your numbers) 0.9 m^2...

 

 

Where did this analysis come from ?

 

how much do the 4 recessed AMRAAMs count for RCS? ;)

[Emu]

If they've honestly gone to that trouble to make something slightly stealthier than a Typhoon, then it's difficult to define it as a success.

[franciwzm]

" If they've honestly gone to that trouble to make something slightly stealthier than a Typhoon, then it's difficult to define it as a success."

 

It is not stealthier then a thypoon: typhoon in air to air configuration has a frontal rcs of 0,3 square metres : please consider that you can subsitute amraam with meteor ,always in semirecessed positon; so pak fa in air to air configuration has bigger rcs in frontal aspect, likely much more in other angles beeing gigantic and not well optimized for side and back rcs; furthermore meteors and r 73 has very different strategic use: r73, even if has less enegagment rang then amramm c and much less then amraam d, is still a bvr missile; meteor is a different class, play like an air intimidation weapon (when planes are still at ground)

With external wepaons pak fa will exceed 1 metres rcs by many metres, since external pylons only dont add rcs linearly to rcs shaped plane but incrementally: when typhoons first played with f22 at langley in 2006 and get constant track at 40km, americans first claimed that f22 had an external pod to increase rcs to better be tracked by base, then denied and a complete silence took place on what happened...

 

Raphale has no semirecessed position for missiles but overall better stealth design so in air to air configuration rcs is pretty much equal

 

Main advantage of gripen on similar aerodinamic and shape design of eurocanards is that is tiny.

 

As enlighted above pak fa thermal signature will be massive, even if slightly reduced from su35 basis : su35 thermal signature is gigantic.

Give f22 thermal signature of a su35 and it will be no more stealthy.

Conformal tanks are beeing integrating on eurocanards, reducing that 0,8/0,9 rcs in full air to ground asset and drag as well.

Edited May 14, 2016 by franciwzm

[Emu]

I have heard that the 0.1-1m2 figure is an overall all-aspect average on other forums, and that by the same measure the F-22 works out at 0.3-0.4m2. Frontal RCS is much less for both.

[franciwzm]

R "I have heard that the 0.1-1m2 figure is an overall all-aspect average on other forums, and that by the same measure the F-22 works out at 0.3-0.4m2. Frontal RCS is much less for both "

 

Offcial rcs is always referred to frontal aspect only : lateral and back rcs are obviosuly much higher, but usually back rcs is not taked in account as thermal signature increase very much from back side ( it is officialy measured just on front engagement)

 

Frontal rcs of pak fa will be no less then 0,5 square metres if it will be properly assembled:; how could it be less with those huge no shielded /curved air intakes ? Eurocanards have all curved air intakes: obviously curved intakes decrease engine power . https://www.google.it/search?q=rafale+air+intakes&rlz=1C1VFKB_enIT600IT600&biw=1680&bih=925&tbm=isch&imgil=e2QKLfHksaIwDM%253A%253BqRqDsq26g8AF0M%253Bhttp%25253A%25252F%25252Fforum.keypublishing.com%25252Fshowthread.php%25253F97863-RCS-of-eurocanards&source=iu&pf=m&fir=e2QKLfHksaIwDM%253A%252CqRqDsq26g8AF0M%252C_&usg=__h7ZC0ypeTlUFx7zz10IugAUbLZs%3D&ved=0ahUKEwjZgtiu49rMAhUFshQKHRLWDVYQyjcIJw&ei=W7w3V5npCYXkUpKst7AF#imgrc=e2QKLfHksaIwDM%3A

 

Official frontal rcs of F22 is 0,0001 square metres, but obviously you must be very precisely allineated to measure such a tiny rcs ! F35 frontal rcs seems to be at least on par from first real flights measurements ; typhoon' captor radar seemed to be able to detect f22 from 40km; (2006 langley encounter) considering you need to reduce rcs by 16 times to cut by half detection distance, and since typhoon can detect 1 square metres rcs 200km+we can speculate that real life rcs of 22 ( not 100% allineated ) could be 1 /( 16* 200/40 ) = 1 / 80 = 0,0125 squre metres.

We can speculate that real life f22 rcs is then 0,0125 square metres.

 

Size matters: F18 pilots with aesa radar claimed that tracking gripens is very hard.

 

Not only shape is important for rcs: thypoon' pilots in 2006 claimed that lateral and back rcs of 22is not dissimilar from typhoon' one,basing on detection range. : that could be true : 85% of eurocanards is not metal but composites, which act like natural RAM .We dont know how much lateral and back rcs of F22 is, but for sure much much much more then 0,0125 of frontal engagements real life one.

We can summarize then that in lateral rcs size and materials play a greater role that in frontal rcs; and back rcs is usually not taken in account beacause of importance of thermal signature. Obviously all wing design such as b2 have great advatanges in reducing lateral rcs, but all wings design or hybrid all wings designs for fighters are yet to come.

Edited May 15, 2016 by franciwzm