Su-57 News and Discussion -version_we_lost_count!-

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Mach 3 isn't such a big challenge, ultimately. The technical specifications on the F-15 show that Boeing has an air superiority aircraft, albeit of the fourth generation, that can achieve Mach 3 speeds.

Mach 3 is a big challenge if you want an LO, agile fighter, and F-15 can't reach Mach 3
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Agility matters a lot less when everyone has HOBS. The PL-10 purportedly can hit 180 degrees off bore-sight; i.e, if you're on a Flanker's six, they'll just lob PL-10 and you're done. Likewise, as I've explained to FBW, you only need enough LO to stop the enemy from hitting you with AIM-120s at range. And once again, Boeing claims that the F-15 can hit 3000 km/h.

https://www.boeing.com/defense/f-15-eagle/

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Agility matters a lot less when everyone has HOBS. The PL-10 purportedly can hit 180 degrees off bore-sight Likewise, as I've explained to FBW, you only need enough LO to stop the enemy from hitting you with AIM-120s at range

They can turn and are designed with stealth in mind unlike Mig-25, Mig-31 or SR-71
And once again, Boeing claims that the F-15 can hit 3000 km/h.

They also stated F-15 limit at Mach 2.5 , likely the site author get lazy and took 1220*2.5 = 3050 km/h without consider that speed of sound change with altitude.Regardless, nothing is more accurate than flight manual
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Radar stealth does two things, first, it screws with missiles, preventing them from having a self-guided lock, and second, it screws with aircraft radar, stopping them from detecting non-emitting fighters at distance. But radar stealth doesn't mean much when it comes to IR. True, the F-22 and F-35 have effective IR coatings, but their effectiveness, as show in pictures, is not comparable to radar stealth. So you're still hittable by IR missiles, unless the laser dazzler scheduled for the F-35 does its work.

As to the F-15 limit at Mach 2.5, note that the manual for the F-15C states that the aircraft is operationally limited to Mach 2.5. The implied maximum aerodynamic speed is Mach 2.6. And it's with the older PW F100-220 engines. The latest 229s have about a 22% thrust increase, suggesting a 10% further increase in speed, so you can hit Mach 2.75.

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That’s a big statement that stealth is merely a missile countermeasure (and aircraft can detect each other just fine) when we have operational pilots across the world now saying they can’t see the f-22 or f-35 in exercises at all until they have already been shot down or until they see them visually.

I think china’s edge treatments on their leading edges suggests they do actually care about the RAM too.

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9 years 6 months

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As to the F-15 limit at Mach 2.5, note that the manual for the F-15C states that the aircraft is operationally limited to Mach 2.5. The implied maximum aerodynamic speed is Mach 2.6. And it's with the older PW F100-220 engines. The latest 229s have about a 22% thrust increase, suggesting a 10% further increase in speed, so you can hit Mach 2.75.

No you can't
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Hi everyody,

this is my first post in this very interesting thread (when is not polluted by fans or hate boys or deleted for unknown reason of course...) Being neither Russian nor American and moreover from an officially "neutral" country I have no interest in those dick measuring endless debates but do follow the serious discussions and pieces of information related to the Su-57.

Let me get back to post #308 from Inst and precisely to that question he raised:

" Is this the real secret of the Su-57? I.e, it's "stealthy", in terms of being LO, but it's willing to sacrifice stealth for speed?"

The answer is yes and is known since MAKS 2009 i.e even before the first flight of T-50-1. At that time, M Pogossian who was in charge of the project at Sukhoi said something like "PAK-FA will incorporate many stealth features BUT NOT to the expense of speed and manoeuvrability" Unfortunately I cannot find the exact reference to provide a link but it was an interview of M Pogossian on an aviation forum.

Therefore, this shows a clear choice from the very beginning of the project and confirms Inst hypothesis. Which by the way gave birth to an interesting debate.

It also explains why the aircraft misses the (in)famous S ducts. Getting rid of the very efficient lifting body concept (the channel between the engines nacelles) which made and still does marvels on the Flanker family would have impacted manoeuvrability. (Not saying that the lifting body is the only reason of the Flanker agility but it definitely contributes to it.) Of course they could have developed other means to restore agility but it would have been costly and time consuming. So why re-invent the wheel to fulfil an essential requirement from the RuAF when your have a proven solution available. The RuAf which by he way seems to view stealth as a valuable asset but definitely not the most important.

OK, I have been long enough.
I will keep following the thread as long as it remains alive... ;)

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4 years 3 months

Posts: 156

Hi everyody,

this is my first post in this very interesting thread (when is not polluted by fans or hate boys or deleted for unknown reason of course...) Being neither Russian nor American and moreover from an officially "neutral" country I have no interest in those dick measuring endless debates but do follow the serious discussions and pieces of information related to the Su-57.

Let me get back to post #308 from Inst and precisely to that question he raised:

" Is this the real secret of the Su-57? I.e, it's "stealthy", in terms of being LO, but it's willing to sacrifice stealth for speed?"

The answer is yes and is known since MAKS 2009 i.e even before the first flight of T-50-1. At that time, M Pogossian who was in charge of the project at Sukhoi said something like "PAK-FA will incorporate many stealth features BUT NOT to the expense of speed and manoeuvrability" Unfortunately I cannot find the exact reference to provide a link but it was an interview of M Pogossian on an aviation forum.

Therefore, this shows a clear choice from the very beginning of the project and confirms Inst hypothesis. Which by the way gave birth to an interesting debate.

It also explains why the aircraft misses the (in)famous S ducts. Getting rid of the very efficient lifting body concept (the channel between the engines nacelles) which made and still does marvels on the Flanker family would have impacted manoeuvrability. (Not saying that the lifting body is the only reason of the Flanker agility but it definitely contributes to it.) Of course they could have developed other means to restore agility but it would have been costly and time consuming. So why re-invent the wheel to fulfil an essential requirement from the RuAF when your have a proven solution available. The RuAf which by he way seems to view stealth as a valuable asset but definitely not the most important.

OK, I have been long enough.
I will keep following the thread as long as it remains alive...

Wellcome framine.

It would be good to see if the engineer said exactly that phrase you mention. Because really in the combats of today supermanoeuvrability has happened to be secondary when the current fighters incorporate missiles HOBS and pilots mounted helmets. It is not necessary to get to 6 of your opponent. This on the one hand and on the other, close combats are increasingly rare.

So it does not make much sense from my point of view to penalize stealth to obtain greater maneuverability, because you wil not take advantage about it.

In addition, we know that the plane has radars in the cheeks to cover a greater angle, precisely to give a greater lethality to the missiles HOBS.

Another thing is to look for more speed, there I no longer enter ....

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Pogossian was an engineer? Sure he wasn't a businessman?

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framige:

to fulfil an essential requirement from the RuAF
what essential requiement is that?

The RuAf which by he way seems to view stealth as a valuable asset but definitely not the most important.
Possibly the same can be said for the USAF as well?

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Pogossian was an engineer? Sure he wasn't a businessman?

as I see you have interests of your biography,...... you enjoy it.

Mikhail Aslanovich Pogosyan (Russian: Михаил Асланович Погосян, April 18, 1956, Moscow) is a Russian aerospace engineer.

In 1979 he graduated with honors from the aircraft manufacturer faculty of the Moscow Aviation Institute and started his career at the engineering plant named after P.O. Sukhoi (now known as the JSC Sukhoy Design Bureau) where continues to work to this day. He started as a designer engineer and then held the posts of the First Deputy Chief Designer (1992-1998), Chairman of Directors Board of the Design Bureau (1995-1999) and, eventually, General Director of the Sukhoi Design Bureau (starting from May 1999).[citation needed]

He is the author of 11 patents and inventions, 14 scientific papers, a Laureate of the State RF Prize in 1997 and Laureate of the Russian Government Prize in 1998, Doctor of Science, is a Corresponding Member of the Russian Academy of Sciences and is a Member of the Entrepreneurial Council at the Russian Government.

On 31 January 2011, he was appointed general director of United Aircraft Corporation (UAC),[2] was replaced in January 2015.

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As to the F-15 limit at Mach 2.5, note that the manual for the F-15C states that the aircraft is operationally limited to Mach 2.5. The implied maximum aerodynamic speed is Mach 2.6. And it's with the older PW F100-220 engines. The latest 229s have about a 22% thrust increase, suggesting a 10% further increase in speed, so you can hit Mach 2.75.

Not even close.

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@moon_light:
if I am not wrong, RVV-BD is the name for export version. Most modern domestic variant would be R-37M. Even when Meteor is a big step in terms of kinematics, R-37M is still much superior in range, speed, warhead and power of its seeker. Of course it is also a much bigger missile

@Inst:
modern IR missiles are ok but still launch position relative to the target matters, both in terms of pure kinematics and also in order to reliably identify and attack the target despite countermeasures. Among them by the way, Su-57 and apparently also F-35 in future will count on DIRCM which will be a hard nut to crack for IR seekers. You are also assuming that radar seekers on missiles will not be able to get a lock on a VLO fighter... this is not very likely, since the fighter will be manoeuvring, trying to run away and far from showing optimally low RCS to the missile's seeker. And because modern seekers will catch even a low RCS once they are near enough. But even then, remind there are some MRAAMs equipped with IR seekers as well, so no need for a plane like in your example to come very near, launch a R-74M2 and outrun an AMRAAM.

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@RALL

I am sure I read Pogossian whole interview and found this statement (maybe not in exactly the same wording) but that was the meaning of it. I don't speak Russian so I read the English version and I don't believe in a translation error because the rest of the interview was written in excellent English.
Additionally the final product (i.e. Su-57) seems to confirm this approach : no S ducts, no rectangular engine exhausts which would make 2,5D (on current engine) or full 3D (on now flight testing type 30 future engine) vectoring thrust impossible, etc.. pointing to agility being seen at least as important as VLO. If it is or not a good choice depends on the RuAF requirements of which AFAIK we don't know much... The plane will be a success not if it is stealthier than the F22 or F35 but if it matches those requirements. At least this is what I think...
Regarding speed I am like you I have no opinion, so many theories and rumours around on that subject.

@Levsha

"what essential requirement is that?"
Manoeuvrability.

"Possibly the same can be said for the USAF as well?"
Possibly but the Americans keep praising stealth which, according to them, will make close combat impossible together with long range AA missiles. Nevertheless both F22 and F35 embark two short range missiles and a cannon...
Reminds me of those brand new F4 Phantom that were sent to VietNam with air-air missiles but no cannon based on the same idea. But after some of them were shot down by MiG-15 which had no missiles but one 37mm and two 25mm guns the Phantoms where rushed back to the US and equipped with a nice Gatling cannon under the nose...

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Regarding super-agility:

having fighters designed with this feature in mind doesn't mean that Russians bet it all on dog-fights due to the inferior nature of their stealth, missiles and avionics, or as if they ignored energy manoeuvrability. This is a frankly lame, self serving kind of BS frequently implied in Western military media. If it was so, their aircraft would load significantly more than 150 rounds for their 30 mm cannon, which is the bare minimum for self defence.

Reality is it was started by them not wanting their pilots not be concerned about handling issues while in the middle of a fight. This affected engine management to avoid chocking, FCS laws and many other aspects of fighter design. Result is they do not have AoA limits or concerns that they will loose the aircraft by moving the nose as much as needed to get the first shot. So just an additional resource in the tool box, nothing less and nothing more. And with the added advantage of avoiding aircraft losses unavoidable in planes with worse handling characteristics:

https://www.youtube.com/watch?v=h97RUPvdg1o

(this video never gets old LOL)

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You do realize the problem isn't that stealth makes WVR dogfighting impossible, right? The problem is that once you get into WVR, missiles with 20-40 km range, 60G maneuver (enough to hit 12G maneuvering fighters), and off-boresight targeting (once again, the example of the PL-10 being able to hit 180 degree off-boresight) means that WVR is not even a knife fight in a phone booth, it's rugby with suicide bombs.

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@RALL

I am sure I read Pogossian whole interview and found this statement (maybe not in exactly the same wording) but that was the meaning of it. I don't speak Russian so I read the English version and I don't believe in a translation error because the rest of the interview was written in excellent English.

"Possibly the same can be said for the USAF as well?"
Possibly but the Americans keep praising stealth which, according to them, will make close combat impossible together with long range AA missiles. Nevertheless both F22 and F35 embark two short range missiles and a cannon...
Reminds me of those brand new F4 Phantom that were sent to VietNam with air-air missiles but no cannon based on the same idea. But after some of them were shot down by MiG-15 which had no missiles but one 37mm and two 25mm guns the Phantoms where rushed back to the US and equipped with a nice Gatling cannon under the nose...

That analogy is so ill-used and obsolete it is painful to read every time it’s repeated. 50 years... that is the time that has passed since Vietnam. Let that sink in. If guns and maneuverability were the two critical factors in air combat, the biplane with dual cannon firing through the prop was both the most maneuverable, and most reliable gun system. We don’t use those now do we?

One, AAM of the Vietnam era had limited coolant, limited firing envelope, limited aspect for which a heat seeker could engage. Pilots from the USAF (specifically) were not trained in their employment. Worse, they didn’t realize captive carry hours could result in dud missiles from repeated stress of flight.

Forward 12-15 years, the Aim-9L was lethal in Falklands. Forward another 5-7 years, HMS and AA-11 (R-73) combination on the MiG-29 and Su-27.

Playing WVR is death. Sure, a Su-22 avioided an AIM-9X over Syria, then died to an AIM-120. Maneuverability isn’t going to save you in a “many vs many” close in fight. Nor will turn radius or thrust to weight ratio. Multiple exercises and studies show this. I can pull up my old thread to show the results.

OODA loop and advantageous position are the biggest factors in “winning” close in. And frankly, modern day fights aren’t going to last long enough for a gun (or lack thereof) to be a factor. The day of two-three circle fights with multiple vertical breaks and extending are done. It only gets an all-aspect missile up your rear..
or nose.

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@LMFS: DIRCCM. Or multi-seeker type tracking. At the shortest ranges, radar is just as good as IR.

The other issue with seeker radar is that some of them are X-band, like fighter radars, but others are Ku-band and higher. Against stealth shaping, radars get worse the higher band you go up, so while a F-22 might be -40 dBsm to X-band, it could easily hit -70 dBsm to Ka band.

===

I am also aware of the problem with the dash target; MICA, for instance, is a medium-ranged air-to-air missile with EO seeker, up to about 100 km. On approach at high Mach, you're going to be detected at very long ranges, and you can be targeted beforehand even if the missile can't acquire a lock and needs data-linking.

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Stealth is both a missile countermeasure and an anti-detection mechanism. In the full-on American stealth aircraft system, you'll have aircraft that are not only undetectable by radar until WVR ranges, but there's also interesting reports that stealth aircraft can get very annoying WVR; even if you can see them, your electronic targeting system might not be able to pick them up due to RCS flicker.

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Against stealth shaping, radars get worse the higher band you go

That is not true. There are many factors involved which will yield an optimal frequency. And the RCS reduction measures will diminish in effectiveness on both sides of that frequency.