Operational Performace Comparison: Viper, Beagle, and Stubby

The F-35 compared with other modern jets.
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southerncross

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Unread post10 Sep 2019, 17:02

ricnunes wrote:Sure, but one has to be aware that modern missiles like the AMRAAM don't chase the aircraft "per se". They "lead pursuit" ...
I don't know if I made myself or my point clear above?

Sure you made the point clear. In the case above, the MiG-31 is supposed to be flying fast, high and straight towards a target (i.e. AWACS), unaware of opposing fighters launching one AMRAAM in its direction. So this lead-pursuit is in this case of no application, since it is the MiG which is flying directly towards the missile. In the original case, it would only start evading maneuvers once the active seeker at the AMRAAM would come online, between 11 and 5 nm from the plane. From that moment onwards, if I understood it correctly, it is only MiG vs. AMRAAM, since the guidance cannot know in what direction the MiG will turn upon perceiving the threat. Maybe you could launch four missiles, two coming from each side to counter the potential MiGs maneouvers, who knows what tactics could be of application.

As to how realistic this scenario is, I guess it all depends in the circumstances. IMHO such assets as a MiG-31 would only be used in face of outright aggression against the territory of Russia, MiGs have not been deployed to Syria for instance. That would mean some assets in theater that substantially change the balance of force and detection capabilities of each side and reinforce the MiG's chances, particularly and as expressed before, the presence of high-end early warning and airspace control assets, and also serious EW... we can theorize a lot about further configurations, but the fundamentals of the MiG vs. AMRAAM confrontation were laid down above.
Anyway, yes I agree that a Mig-31 updated with the latest electronics, namely but not only with a new radar, that it would be an enemy to be reckoned with. Although such (updated) Mig-31 wouldn't have much of a chance against a F-35, it would IMO be a major threat to any existing 4.5th gen fighter aircraft. Well, my 2 cents anyway...

See above. The difference in RCS gives a big advantage to the F-35 one on one, sure. But if in-theater radars are used with extreme performance (as it is claimed for some of them), the MiG is not blind anymore and this changes everything because now its kinematics can shine. In the hypothetical case that the airspace is accurately monitored, they could just hit and run with very low attrition rates, without any opposing fighter being currently able to outrun them or having a longer ranged missile (I don't know what Meteor can ultimately do, but we also lack real data about R-37M). So it really depends on the situation and what the real capabilities of those assets are, again IMHO. What strikes me the most are the slim chances a conventional MRAAM has against such fast, high-flying target, even unaware. F-35 would in any case, in absence of other weapons like new long range missiles or the very Meteor, need to fly as high and fast as possible to max the chances of the attack. It could also use its stealth and wait until it is very close to the MiG to give the AMRAAM better chances, but then it would be risking the MiG launching its missiles towards its main target too.
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Unread post10 Sep 2019, 17:45

southerncross wrote:True, that makes it questionable that it can be done without AB.

Mig-31 will fly with AB, but it can carry very significant amount of fuel

southerncross wrote:What I refer is that they (IMHO too) should work like a leading-edge flap, helping to keep airflow attached at high AoA (the body of the plane is shaped as a big airfoil) and so improve the lift curve without needing such big LERX as Flankers have, which are in the end drag-generating devices. So, at supersonic speed the plane could level the LEVCONS and reduce its drag, this should help flying faster and hence also higher. I don't know if their deflection in level flight and thin air can help improving lift or affecting trim too but I would not be surprised if that was the case, since they alter the profile of the lifting body.

IMHO, LEVCON isn't less draggy compared to LERX or Chines even when it is in level position because LEVCONS are significantly bigger.
Furthermore, I don't think you will be flying at high AoA and high speed at the same time.

southerncross wrote:Su-35S' service ceiling is 18 km, so a bit lower than the other three. In any case, the incentive of high and fast flight for air superiority I think was clear before and more even after seeing Spurts' figures. The faster and higher you fly, the more challenged attacking missiles will be. If you couple that with markedly better maneuverability than MiG-31 then you get a fairly difficult target to beat.

I would put the service ceiling of F-15 at 60k ft too base on the manual.
While flying high and fast certainly adding benefit for air superiority, it is not the wise move against air defense.
Moreover, while Su-57 and F-22 will have much better agility than Mig-31 at low and medium altitude, I don't think either will have better agility than Mig-31 at 60k ft.
southerncross wrote:Only to be clear, the way I read your diagram is a frontal RCS of ca. 0.01 for the AGM-86, not 0.001.

It shown the fluctuation between 0.01 and 0.001, since AMRAAM is dozen times smaller than AGM-86, I assume its RCS is closer to 0.001 spikes than 0.01 spikes
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Unread post10 Sep 2019, 19:03

garrya wrote:
southerncross wrote:True, that makes it questionable that it can be done without AB.

Mig-31 will fly with AB, but it can carry very significant amount of fuel


Yep. There's an account of a MiG-31 making a 620 mile run at Mach 2.6. Armed. (In the days after KAL 007, when the USAF moved F-15s into the area the USSR countered with MiG-31s.)
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Unread post10 Sep 2019, 22:01

southerncross wrote:So this lead-pursuit is in this case of no application, since it is the MiG which is flying directly towards the missile. In the original case, it would only start evading maneuvers once the active seeker at the AMRAAM would come online, between 11 and 5 nm from the plane.


Well, that's even worse (and actually much worse) for the Mig-31.
With a closure rate of Mach 6.5 and if the AMRAAM seeker activates at 11 nm then the Mig-31 pilot will only have 11 seconds to react or if the seeker activates at 5 nm then the same pilot will only have 5 second to react!
In any case (specially in the later) by the time that the pilot realizes that's being locked by an AMRAAM (via RWR) to the time to actually pull the stick and the aircraft to actually start responding, it's basically the time that's left for the AMRAAM to hit and kill the Mig. So and basically, game-over (for the Mig-31)!

southerncross wrote:From that moment onwards, if I understood it correctly, it is only MiG vs. AMRAAM, since the guidance cannot know in what direction the MiG will turn upon perceiving the threat. Maybe you could launch four missiles, two coming from each side to counter the potential MiGs maneouvers, who knows what tactics could be of application.


I can't see any reason why the AMRAAM can't lead pursuit based on it's radar/seeker's data/input. The target locks the aircraft which gives a very accurate position of the enemy aircraft in any relative direction (elevation, azimuth and range) from the missile, it has onboard computers, so there's no reason why the AMRAAM can't lead pursuit based on its radar/seeker data alone.

southerncross wrote:See above. The difference in RCS gives a big advantage to the F-35 one on one, sure. But if in-theater radars are used with extreme performance (as it is claimed for some of them), the MiG is not blind anymore and this changes everything because now its kinematics can shine. In the hypothetical case that the airspace is accurately monitored, they could just hit and run with very low attrition rates, without any opposing fighter being currently able to outrun them or having a longer ranged missile (I don't know what Meteor can ultimately do, but we also lack real data about R-37M). So it really depends on the situation and what the real capabilities of those assets are, again IMHO.


Well, I believe that it was explained to you already that you (or in this case the Russians) cannot rely on those very big radars in order to counter a stealth threat like the F-35.
There are some members here that can explain you better than I (hornetfinn being one example) but just to counter some of the examples that you mentioned earlier:
- If you use the Voronezh example (which detects small football sized targets at 6000/8000km) is a no-go since it can only reliably detect such small targets in space. Or more precisely, you can even read the following in the wikipedia entry about the Voronezh radar:
Voronezh-DM (77Ya6-DM) works in the decimeter range (UHF) and was designed by NPK NIIDAR. It has a range of up to 10,000 km and is capable of simultaneously tracking 500 objects.[9][10] In 2015, its maximum range is 10,000 km. Its horizon range is 6000 km and vertical range is 8000 km (Due to radar horizon, this range is only apply if target is located at altitude of several thousand kilometers


Source here:
https://en.wikipedia.org/wiki/Voronezh_radar

For starters, VHF/UHF radars have the following huge disadvantages besides all that were already mentioned (such as static not-mobile, very large and thus easy targets):
1- They concentrate the focus of their energy in a quite narrow field of regard in terms of elevation. Since the Voronezh seems to be more focused on detecting space targets (namely incoming ballistic missiles and warheads/entry vehicles) this more powerful narrow field of regard is aimed more towards space which makes the Voronezh radar pretty much useless against a stealth atmospheric target (i.e. F-35).
2- VHF/UHF are known to be easy or very susceptible to jamming.
3- Stealth or very low RCS is also useful to hide aircraft from VHF/UHF radar (i.e. these radars have a much harder time to detect stealth aircraft than non-stealth aircraft).
4- Taking points 1-, 2- and 3- all together it's relatively easy to devise tactics which allows the F-35 to evade even better such radars. An easy tactic would be to have some of the F-35 flying at lower altitudes - these would never be detected by such VHF/UHF radars due to the reasons mentioned on previous points.

Also as others already told you, not only VHF/UHF radar would still have a very hard time to detect the F-35 but and in case of a lucky F-35 detection, this wouldn't be an accurate track. And even if you sent Mig-31 afters these faint non-accurate tracks, the F-35 would still and always detect the Mig-31 first.

So, as you can see, so many things that could go wrong with the VHF/UHF radars combined with a varied number of other assets while many things would go easy and well solely with the F-35 - Usually (if not always) the easier solution wins over the complex one!

Lastly, IMO one of the biggest evidence of the superiority of the F-35 (or F-22) is the fact that the Russians are attempting to develop something along those lines, the Su-57, the Chinese with the J-20 and J-31, the Franco-German with the FCAS, the British with the Tempest, the ... with the ..., etc, etc...
In the end Stealth is one of those groundbreaking technologies which revolutionizes aerial warfare, like for example the Jet engine and the air-to-air missile was before it. You'll either have it or you'll be left behind, period.
Well, My 2 cents anyway!
A 4th/4.5th gen fighter aircraft stands about as much chance against a F-35 as a guns-only Sabre has against a Viper.
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Unread post10 Sep 2019, 22:06

My missiles are indeed using a lead pursuit. I did have a bug in my horizontal guidance using a 0.1s step interval as it was initially set up for a 1s step interval.
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Unread post10 Sep 2019, 23:09

garrya wrote:Mig-31 will fly with AB, but it can carry very significant amount of fuel

IIRC 720 km combat radius @ 2.35M
IMHO, LEVCON isn't less draggy compared to LERX or Chines even when it is in level position because LEVCONS are significantly bigger.

LERX creates vortexes and hence create drag, I don't know how relevant this is in level flight so I stand to be corrected in case they don't have a significant impact on the aircraft's overall drag. LEVCONS, at least in the form in which they are in Su-57, seem to be there to ensure the body's airfoil produces lift at high AoA. They deploy similarly to the wing's leading edge slats, during turning and in high AoA in general, see picture. I assume they work as a leading edge rather than as a vortex generation device, they should have lower drag when in level position.
Furthermore, I don't think you will be flying at high AoA and high speed at the same time.

No of course, what I mean is that such lifting augmentation devices as LERX, that AFAIK produce constant drag, can be kept at a minimum because the lift contribution of the body is very big and can be used even at high AoA due to LEVCONS, that is my understanding. If you compare the Su-57's vortexes with those of Flankers at high AoAs you will see quite a difference.
I would put the service ceiling of F-15 at 60k ft too base on the manual.

OK thanks
While flying high and fast certainly adding benefit for air superiority, it is not the wise move against air defense.

That would be interesting to check. I assume a SAM will meet the same challenges an AAM does, amplified by a lower and slower launch position but with less weight and volume restrictions. Aero layouts of many SAMs I know don't seem much better than AAMS like AIM-120 in terms of control surfaces, we would need to look in detail.
Moreover, while Su-57 and F-22 will have much better agility than Mig-31 at low and medium altitude, I don't think either will have better agility than Mig-31 at 60k ft.

Why? Their layout should be much better producing lift, so in the end it would depend on how much fuel they have / how fast they can fly in a given situation. Both should be capable of flying between 2 and 2.5M most probably.
It shown the fluctuation between 0.01 and 0.001, since AMRAAM is dozen times smaller than AGM-86, I assume its RCS is closer to 0.001 spikes than 0.01 spikes

Ok I see.
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Unread post10 Sep 2019, 23:41

@ricnunes:

to the first part of your post re. the AMRAAM - MiG scenario, I can see your points but in the end I have more trust in an actual simulation that in anyone's estimations. It was not so clearly cut and the result only supports well known strategies for air superiority. So I am not so convinced as you are and that is perfectly fine.

To the second part, re. the additional AD assets: no one here can explain to me the capabilities of Voronezh in combination with other high-end radars because they are highly classified, and other reliable sources have completely opposite opinions to the ones you expressed. We can discuss a bit more about this in the air power or other appropriate thread if you so wish. But in the end such systems are complex and very little known so to make progress in understanding them even minimally is not an easy task.

Re. LO design, I agree it is a must right now and that is I think acknowledged by almost all militaries and designers, no question.
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Unread post11 Sep 2019, 09:25

southerncross wrote:LERX creates vortexes and hence create drag, I don't know how relevant this is in level flight so I stand to be corrected in case they don't have a significant impact on the aircraft's overall drag. LEVCONS, at least in the form in which they are in Su-57, seem to be there to ensure the body's airfoil produces lift at high AoA. They deploy similarly to the wing's leading edge slats, during turning and in high AoA in general, see picture. I assume they work as a leading edge rather than as a vortex generation device, they should have lower drag when in level position.
No of course, what I mean is that such lifting augmentation devices as LERX, that AFAIK produce constant drag, can be kept at a minimum because the lift contribution of the body is very big and can be used even at high AoA due to LEVCONS, that is my understanding. If you compare the Su-57's vortexes with those of Flankers at high AoAs you will see quite a difference.

To generate more lift at high AoA, LERX and LEVCONS both produce vortex to delay flow separation. In level flight or low AoA, LERX doesn't generate vortex.
LERX operating principles:
LERX.PNG

LERX at low AoA without vortex:
16781151991_682af4bff2_b.jpg

LEVCON's vortex:
254699.jpg


southerncross wrote:That would be interesting to check. I assume a SAM will meet the same challenges an AAM does, amplified by a lower and slower launch position but with less weight and volume restrictions. Aero layouts of many SAMs I know don't seem much better than AAMS like AIM-120 in terms of control surfaces, we would need to look in detail

Generally speaking, SAM has longer motor burn time and less wing load than AMRAAM
Image
Image

southerncross wrote:Why? Their layout should be much better producing lift, so in the end it would depend on how much fuel they have / how fast they can fly in a given situation. Both should be capable of flying between 2 and 2.5M most probably.

Their layouts are much better at producing lift at high AoA, subsonic velocity. At level flight and high supersonic, they aren't more optimized than Mig-31.
Neither Su-57 nor F-22 will be cruising between Mach 2 and 2.5. Mach 2 is their top speed, where already at the edge of their envelope where they can cause damage to the composite structure and the coating. They aren't as optimized for high supersonic fly as mig-31, they can't carry as much fuel or fly as high. Most probably they will be cruising at Mach 1.6 to 1.7
It is believed that the target maximum speed of the T-50 is around Mach 2. The goal was originally Mach 2.35, but this was reduced to Mach 2.1 and then to the current figure, compared to Mach 2.25 for the Su-35S. The main reason for the difference is that the T-50 uses more composite materials in its primary structure than the Su-35S, which makes heavy use of titanium.

https://aviationweek.com/awin/sukhoi-t- ... nnovations

southerncross wrote:To the second part, re. the additional AD assets: no one here can explain to me the capabilities of Voronezh in combination with other high-end radars because they are highly classified, and other reliable sources have completely opposite opinions to the ones you expressed. We can discuss a bit more about this in the air power or other appropriate thread if you so wish. But in the end such systems are complex and very little known so to make progress in understanding them even minimally is not an easy task.

I don't want to go off-topic too much on Voronezh, but as others have mentioned while Voronezh has advantages such as being very powerful with long detection range, it has others disadvantage such as being a gigantic fixed radar, lacking over the horizon capability. Strictly speaking, you can combine Mig-31 with Voronezh to alleviate the RCS downside. However, it is markedly easier to combine F-35 and Arleigh Burke to alleviate the missile range downside. IMHO, combining Mig-31 and Voronezh to counter F-35 is like combining F-15 with Sea-Based X-Band to counter Su-57. A bit too outrageous for my taste
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Unread post11 Sep 2019, 18:33

garrya wrote:To generate more lift at high AoA, LERX and LEVCONS both produce vortex to delay flow separation. In level flight or low AoA, LERX doesn't generate vortex.

Though I am no aero guy, I am familiar with these principles. I would dare disputing that LEVCON's function in the Su-57, despite its very name, consists simply in generating vortexes, or at least I am not seeing them in the air displays. Only the very tip of it creates them, and actually they form mainly on the chines after the LEVCON, as seen in the picture you posted. The size of the vortexes is very small for a plane that declares (as in the patent) trying to bring low speed aero qualities to new levels, compared to their relative size in planes of the 4th. gen., so I am assuming that they are using a different approach to create lift at high AoA. In this sense, the moving leading edge of the LEVCON provides a smoother path for the airflow to remain attached to the lifting surface instead of stalling it, the same way leading edge flaps work. Coherently, we don't see any vortexes being generated at the LEVCON's leading edge.

In general it is assumed that LEVCONs being a movable device allow for a more manageable lift augmentation system than LERX or chines. Another of the patent-stated PAK-FA design goals is to increase supersonic performance and specifically long range supersonic flight. I am looking for ways in which they may have substantially reduced the drag of a plane which is otherwise also required to have a very high degree of maneuverability, so a deployable device like the LEVCON springs immediately to mind. Of course I assume it is not one thing only but the whole that counts, but still some unique design features could help meeting such requirements.
LERX at low AoA without vortex:

Yes, I might be wrong I know. Nevertheless, there is always a certain AoA in order to fly and that means that there is always a relative high pressure below the LERX that tends to scape upwards around its leading edge, provoking vortexes, and in fact this effect would only increase with high load and/or in thin air. Seeing how this phenomenon (in the form of wing-tip vortex) is fought in airliners as a serious source of drag, I can imagine it could be beneficial to rely on other forms of high-AoA lift augmentation devices instead of a fixed one, purposely built to induce drag-generating vortexes. Still quantifying the relevance of this issue is not really feasible for me.
Generally speaking, SAM has longer motor burn time and less wing load than AMRAAM

True, other AAMs have such strakes too. Conversely, other SAMs doesn't have them. Others have TVC. That is why I say it should be checked in detail. In general the kinematic challenge remains and I understand this was one of the main motivations behind supercruise at high altitude for ATF and MFI/PAK-FA.
Their layouts are much better at producing lift at high AoA, subsonic velocity. At level flight and high supersonic, they aren't more optimized than Mig-31.

Still wing loading is lower. And they would not need to be as optimized as MiG-31. Their engines are on another level.
Neither Su-57 nor F-22 will be cruising between Mach 2 and 2.5. Mach 2 is their top speed, where already at the edge of their envelope where they can cause damage to the composite structure and the coating. They aren't as optimized for high supersonic fly as mig-31, they can't carry as much fuel or fly as high. Most probably they will be cruising at Mach 1.6 to 1.7

In reality for MiG-31 "cruising" does not mean the same as for F-22 and Su-57 in the sense of flying w/o AB. It is most probably able to sustain that speed further, but still data at least for the Su-57 is missing, claims are 1500 km in supersonic which would be similar to what MiG-31 manages to do. Max. speed of F-22 is 2.25 M IIRC, damage to the coatings being the main reason behind it if I am not wrong.

In any case it would be nice to see the possibilities of such platforms against AAMs and SAMs, while flying at 50 kft / 1.6-1.8M. I will try to find some information about it.
It is believed that the target maximum speed of the T-50 is around Mach 2. The goal was originally Mach 2.35, but this was reduced to Mach 2.1 and then to the current figure, compared to Mach 2.25 for the Su-35S. The main reason for the difference is that the T-50 uses more composite materials in its primary structure than the Su-35S, which makes heavy use of titanium.
https://aviationweek.com/awin/sukhoi-t- ... nnovations

There were actual quotes from officials referring the limitation of the maximum speed to 2 M because of the fins' structural resistance. But then the variable intakes would be just an overkill and in general a bad engineering solution (heavy, complex and expensive). Recent claims are cruising speed 2 M, max speed 2.45 M. We just don't know, but to me the fact that such complex intakes are implemented is an indication that flying above 2 M is a "must" and not a "nice to have" requirement in the program.

To the radars issue, as a final note from my side: the central idea behind an IADS is that all assets work together to complement each other. So not only Voronezh but all other available radars and detectors should be used, depending of course on how thoroughly this concept is implemented, which as a matter of fact leaves often much to desire. MiGs are being given this capability only now, it seems, even when already long time ago they could share information among them:

https://iz.ru/873658/aleksei-ramm-aleks ... htab-ataki

Generally speaking, I think this complex reality of the air defence just needs to be kept in mind in order not to over- or underestimate the effects of any particular weapons system.
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Unread post12 Sep 2019, 10:00

southerncross wrote:Though I am no aero guy, I am familiar with these principles. I would dare disputing that LEVCON's function in the Su-57, despite its very name, consists simply in generating vortexes, or at least I am not seeing them in the air displays. Only the very tip of it creates them, and actually they form mainly on the chines after the LEVCON, as seen in the picture you posted. The size of the vortexes is very small for a plane that declares (as in the patent) trying to bring low speed aero qualities to new levels, compared to their relative size in planes of the 4th. gen., so I am assuming that they are using a different approach to create lift at high AoA. In this sense, the moving leading edge of the LEVCON provides a smoother path for the airflow to remain attached to the lifting surface instead of stalling it, the same way leading edge flaps work. Coherently, we don't see any vortexes being generated at the LEVCON's leading edge.
In general it is assumed that LEVCONs being a movable device allow for a more manageable lift augmentation system than LERX or chines. Another of the patent-stated PAK-FA design goals is to increase supersonic performance and specifically long range supersonic flight. I am looking for ways in which they may have substantially reduced the drag of a plane which is otherwise also required to have a very high degree of maneuverability, so a deployable device like the LEVCON springs immediately to mind. Of course I assume it is not one thing only but the whole that counts, but still some unique design features could help meeting such requirements.
Yes, I might be wrong I know. Nevertheless, there is always a certain AoA in order to fly and that means that there is always a relative high pressure below the LERX that tends to scape upwards around its leading edge, provoking vortexes, and in fact this effect would only increase with high load and/or in thin air. Seeing how this phenomenon (in the form of wing-tip vortex) is fought in airliners as a serious source of drag, I can imagine it could be beneficial to rely on other forms of high-AoA lift augmentation devices instead of a fixed one, purposely built to induce drag-generating vortexes. Still quantifying the relevance of this issue is not really feasible for me.

Su-57 has very good low speed handling quality mainly, a big part of it thanks to the 3D TVC and the full moving tails, you see vortex form at su-57 chines because low aspect ratio wing with high sweep always generate vortex at high AoA, same goes for F-35 and F-22 chines. Thus, even when the moving LEVCONS doesn't generate vortex, the chines still does, so it doesn't help with reducing drag. TBH, at high AoA a moveable LEVCONS or Canard could be steer so that they are more optimized to produce lift but I don't see how LEVCONS or canard could possibly have lower drag than LERX or chines at level flight or low AoA.
LERX start to generate vortex at about 10 AoA
leading edge extension and lift.PNG


southerncross wrote: Still wing loading is lower. And they would not need to be as optimized as MiG-31. Their engines are on another level.

Lift is proportional to square of velocity, so some increase in velocity and bring lift up significantly.
IMHO, neither F-119 nor izdeliye 30 are as optimized to high supersonic as D-30F6.

southerncross wrote:True, other AAMs have such strakes too. Conversely, other SAMs doesn't have them. Others have TVC. That is why I say it should be checked in detail. In general the kinematic challenge remains and I understand this was one of the main motivations behind supercruise at high altitude for ATF and MFI/PAK-FA.

Not all SAM have strakes but long range one all have more fuel to burn than AAM, because they have more fuel to burn there average velocity is likely higher. If the missile fly faster, then it can produce more lift with the same wing area. You see where I am heading at?
AAM with strakes or big wing are designed for high altitude operation.

southerncross wrote:In reality for MiG-31 "cruising" does not mean the same as for F-22 and Su-57 in the sense of flying w/o AB. It is most probably able to sustain that speed further, but still data at least for the Su-57 is missing, claims are 1500 km in supersonic which would be similar to what MiG-31 manages to do

I don't think Su-57 supersonic flight range is equal or even close to Mig-31 because Mig-31 can carry 56% more fuel and it can cruise at much higher altitude where the air is thinner thus reduce fuel consumption.
We don't have exact details about the alleged 1500 km supersonic operation either, could be with internal fuel but could be with supersonic tank, it is most probably at low supersonic such as Mach 1.1 -1.1.15 rather than 1.6-1.7.

southerncross wrote:There were actual quotes from officials referring the limitation of the maximum speed to 2 M because of the fins' structural resistance. But then the variable intakes would be just an overkill and in general a bad engineering solution (heavy, complex and expensive). Recent claims are cruising speed 2 M, max speed 2.45 M. We just don't know, but to me the fact that such complex intakes are implemented is an indication that flying above 2 M is a "must" and not a "nice to have" requirement in the program.

A variable inlet can help generate higher dynamic thrust at supersonic speed, hence better supersonic acceleration, higher top speed doesn't have to be the cause. Furthermore, I haven't heard any official claims about increasing back cruising speed of Su-57 to Mach 2 and top speed to Mach 2.45 , it could be the idea of some internet fanboy but doesn't sound at all realistic, sorta like someone who claimed F-22 reached Mach 2.8
southerncross wrote:To the radars issue, as a final note from my side: the central idea behind an IADS is that all assets work together to complement each other. So not only Voronezh but all other available radars and detectors should be used, depending of course on how thoroughly this concept is implemented, which as a matter of fact leaves often much to desire. MiGs are being given this capability only now, it seems, even when already long time ago they could share information among them:
Generally speaking, I think this complex reality of the air defence just needs to be kept in mind in order not to over- or underestimate the effects of any particular weapons system.

I throughout agree with you that combine arms is the central idea for all militaries.
The outrageous part of your idea is a strategic radar for ballistic missiles defense being used to deal with tactical fighter. Is it plausible US will use sea-based X-band in combination with F-15C or F-16 to attack Su-57?. It is a rhetorical question. You see what I am getting at?
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ricnunes

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Unread post12 Sep 2019, 11:33

garrya wrote:I throughout agree with you that combine arms is the central idea for all militaries.
The outrageous part of your idea is a strategic radar for ballistic missiles defense being used to deal with tactical fighter. Is it plausible US will use sea-based X-band in combination with F-15C or F-16 to attack Su-57?. It is a rhetorical question. You see what I am getting at?


That's exactly on of my points about this discussion of "Combat aircraft/F-35 vs Voronezh" if you will. While the Voronezh is technically capable of detecting a "football sized" target at 6000km away, this again is only possible if this target is in space (outside the Earth's atmosphere). This is due to a combination of:

1- If the target was flying lower into the atmosphere is would be blocked in terms of Line-of-Sight (LOS) or by the Earth's curvature and thus even if the radar was able to detect the target at a certainly very long range, due to these reasons alone it wouldn't.

2- I would say that space has much, much less background noise compared to the Earth's atmosphere which by itself should allow radars to detect smaller target at longer ranges, this up to distances not possible against targets flying in the Earth's atmosphere (such as the F-35 or any aircraft for that matters).

3- Then there's the energy focus issue regarding VHF/UHF radars which I mentioned in my previous post - they can only concentrate most of their energy on a rather limited field of regard. This seems to be a limitation regarding VHF/UHF radars and as such laws of physics which cannot be bended, if you will. And even if you could steer the Voronezh energy focus to a "lower/shallower angle" (and note, I don't doubt that this is possible) what would be farthest possible detection range? The answer would be something between 400km to 600km, this against to due to LOS issues related to the fact that the Earth is round, or resuming due to the Earth's curvature (unless you're one of those guys that believe that Earth is flat, LoL :mrgreen: ). So doing this would be a waste of resources since it would leave a major gap in terms of Russia's capability to be able to detect incoming ICBMs (likely with nuclear MIRV or MARV warheads).


In reality the best VHF/UHF radar that the Russians currently have against (atmospheric) aircraft like the F-35 is the NEBO-M. This one has capability of detecting a 1 square meter RCS target at a range of 400km but this against in a focus (-45º to 45º) mode/cone as opposed to a 360º detection whose detection range is lower.
So even with this "best" Russian radar system, the detection range against a F-35 would be limited. According to my calculations something like 90km (at best) and this while in focus mode and again in a best case scenario.
A 4th/4.5th gen fighter aircraft stands about as much chance against a F-35 as a guns-only Sabre has against a Viper.
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Unread post13 Sep 2019, 01:05

garrya wrote:Thus, even when the moving LEVCONS doesn't generate vortex, the chines still does, so it doesn't help with reducing drag.

I see the relative size difference of those elements in Su-57 vs. 4th gen fighters as a an incremental improvement. The vortexes, in a right amount, can still help keep the airflow in place. Still is only a theory so maybe you are right.
IMHO, neither F-119 nor izdeliye 30 are as optimized to high supersonic as D-30F6.

Typically for supersonic flight you want a turbojet with very high specific thrust. The MiG-31 instead has an engine with roughly the BPR of the F135 rather than that of the F119. But of course other parameters can and will be optimized for speed. If its supersonic flight is in AB mode, then maybe the BPR is not so relevant.
Not all SAM have strakes but long range one all have more fuel to burn than AAM, because they have more fuel to burn there average velocity is likely higher. If the missile fly faster, then it can produce more lift with the same wing area. You see where I am heading at?

Yes I think I get it. What I am not sure is that SAMs have generally an energy advantage vs. AAMs, both are designed according to what is deemed necessary and not more. Let's say, SAMs are bigger because they can AND need to. Then, there are indeed high-end SAMs which are indeed faster than common AAMs, while other SAMs are direct conversions of AAMs. The biggest and fastest among the later (i.e. R-37M) reach similar speeds to the fastest SAMs (6 M estimated for R-37, 7 M for S-400 missiles). With the difference, that the carrier can make an influence for better or worse on that while for SAMs there is no such possibility.
I still don't understand why did you say that flying high is worse against SAMs. You mean "high" as opposed to hiding close to ground or high compared to other plane's cruising altitude? Radar horizon is just one piece of the puzzle if we talk about IADS, other being airborne and OTH radars that will not be affected by altitude that much.
I don't think Su-57 supersonic flight range is equal or even close to Mig-31 because Mig-31 can carry 56% more fuel and it can cruise at much higher altitude where the air is thinner thus reduce fuel consumption.
We don't have exact details about the alleged 1500 km supersonic operation either, could be with internal fuel but could be with supersonic tank, it is most probably at low supersonic such as Mach 1.1 -1.1.15 rather than 1.6-1.7.

Without knowing the internal fuel or ceiling of the Su-57 we cannot be sure, even when your estimation is reasonable to me. But if the MiG-31 is using AB it will be consuming fuel at a relative rate maybe 3 or 4 times faster than the Sukhoi, that certainly makes a difference.
A variable inlet can help generate higher dynamic thrust at supersonic speed, hence better supersonic acceleration, higher top speed doesn't have to be the cause.

That is a possibility, in any case the performance difference between both types of intakes increases strongly with the speed. The patent claims the fixed one in the F-22 is limited above 2M and the variable one in the Su-57 valid up to 3M.
Furthermore, I haven't heard any official claims about increasing back cruising speed of Su-57 to Mach 2 and top speed to Mach 2.45 , it could be the idea of some internet fanboy but doesn't sound at all realistic, sorta like someone who claimed F-22 reached Mach 2.8

It was not an internet fanboy, but still it does not mean it was correct by any means. I don't see it wildly unrealistic but I have no hard data, just hints here and there.
I throughout agree with you that combine arms is the central idea for all militaries.
The outrageous part of your idea is a strategic radar for ballistic missiles defense being used to deal with tactical fighter. Is it plausible US will use sea-based X-band in combination with F-15C or F-16 to attack Su-57?. It is a rhetorical question. You see what I am getting at?

Fair enough. I am not saying such assets are there for small tactical matters, only that every target detected by them will immediately make part of the IADS global picture, be evaluated, prioritised and actioned as deemed necessary, especially if tactically relevant i.e. threatening own assets. I will leave it there and hope this seemingly unsinkable topic does not come afloat again in this thread, as it was just a side note to the 1 vs 1 approach.
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Unread post13 Sep 2019, 05:40

southerncross wrote:Typically for supersonic flight you want a turbojet with very high specific thrust. The MiG-31 instead has an engine with roughly the BPR of the F135 rather than that of the F119. But of course other parameters can and will be optimized for speed. If its supersonic flight is in AB mode, then maybe the BPR is not so relevant.

Mig-31 engine has high BPR but the overall pressure ratio is low, and there are others relevant parameters.


southerncross wrote:Yes I think I get it. What I am not sure is that SAMs have generally an energy advantage vs. AAMs, both are designed according to what is deemed necessary and not more. Let's say, SAMs are bigger because they can AND need to. Then, there are indeed high-end SAMs which are indeed faster than common AAMs, while other SAMs are direct conversions of AAMs. The biggest and fastest among the later (i.e. R-37M) reach similar speeds to the fastest SAMs (6 M estimated for R-37, 7 M for S-400 missiles). With the difference, that the carrier can make an influence for better or worse on that while for SAMs there is no such possibility.

SAM is not limited in size and weight as AAM, if you want more velocity and range out of a SAM, you can keep making it bigger, you can't do the same to an AAM. R-37 among the biggest AAM to date is only 600 kg and 4.2 meters long. By contrast, SM-6 is 6.6 meters and weight 1500 kg, S-200 weight 7100 kg and with the length of 10.7 meters, and there are many SAM with greater size and weight. Thanks to their greater size, SAM can carry more propellant, thus come significantly greater cruising velocity
Even though, AMRAAM launched at high altitude can reach mach 6, however, SAM can be easily designed to be far faster than any AAM if their role requires them, THAAD can reach Mach 8.2, Arrow can reach Mach 9, SM-3 can reach Mach 13.


southerncross wrote:I still don't understand why did you say that flying high is worse against SAMs. You mean "high" as opposed to hiding close to ground or high compared to other plane's cruising altitude? Radar horizon is just one piece of the puzzle if we talk about IADS, other being airborne and OTH radars that will not be affected by altitude that much.

High compared to other plane's cruising altitude, because when you are high and fast you can't change direction as quick, it is likely that you keep flying deep inside the no escape zone of SAM site even after you have detected them. Furthermore, high and fast targets are easier to detect. If you are easily to detect and you fly into their lethal envelope then it will not end well. OTH radars are not accurate and they are very susceptible to cruise missile attack compared to mobile radar.


southerncross wrote:Without knowing the internal fuel or ceiling of the Su-57 we cannot be sure, even when your estimation is reasonable to me. But if the MiG-31 is using AB it will be consuming fuel at a relative rate maybe 3 or 4 times faster than the Sukhoi, that certainly makes a difference.

AFAIK, the internal fuel capacity of Su-57 is 10.3 tons
the ceiling of Su-57 is likely very similar to F-22 because they have similar missions, similar cruising velocity, similar top speed, similar pilot flight suit

southerncross wrote:That is a possibility, in any case the performance difference between both types of intakes increases strongly with the speed. The patent claims the fixed one in the F-22 is limited above 2M and the variable one in the Su-57 valid up to 3M.

I haven't seen the pattern for F-22/Su-57's inlet or their claimed limitation. It is important to keep in mind that fixed inlet doesn't always mean Mach 2 limitation.
F-8U-3 can reach Mach 2.9 with fixed inlet
Image
Furthermore, there are many other possible limitations such as canopy, structure, coating. Just because the composition of inlet and engine can let you fly faster than a particular speed, doesn't mean there isn't any others factor limit you to velocity below that. For example, DSI inlet and F-135 engine can generate enough thrust to allow F-35 fly faster than Mach 1.6 but it is still limited to Mach 1.6
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Unread post13 Sep 2019, 19:57

garrya wrote:Even though, AMRAAM launched at high altitude can reach mach 6, however, SAM can be easily designed to be far faster than any AAM if their role requires them, THAAD can reach Mach 8.2, Arrow can reach Mach 9, SM-3 can reach Mach 13.

If you notice, those high speed systems you refer are ABMs, it does not seem that the ones meant against planes do have that performance. One could argue that aircraft could carry even bigger AAMs if that was interesting, the same they carry big AGM/ASMs

High compared to other plane's cruising altitude, because when you are high and fast you can't change direction as quick, it is likely that you keep flying deep inside the no escape zone of SAM site even after you have detected them. Furthermore, high and fast targets are easier to detect. If you are easily to detect and you fly into their lethal envelope then it will not end well.
True, and as we just see the engagement zone of the missile vs, a high-flying, fast target also shrinks notably. I don't dispute that you have a point, I just don't know what of the two competing factors weights more and in general I take for granted that it will depend on the concrete case as we are seeing in the thread.
OTH radars are not accurate and they are very susceptible to cruise missile attack compared to mobile radar.

Those of Container type are said to be reasonably precise (they use only one reflection on the ionosphere) and capable of detecting the launching of those CMs 3000 km away. So they can put the whole AD to intercept them straight away.
AFAIK, the internal fuel capacity of Su-57 is 10.3 tons

All these figures are speculative, even when that may be a good guess.
the ceiling of Su-57 is likely very similar to F-22 because they have similar missions, similar cruising velocity, similar top speed, similar pilot flight suit

Let's see. They obviously should have similar missions, but they still they have differences and to figure them out can be the most interesting part. :D
I haven't seen the pattern for F-22/Su-57's inlet or their claimed limitation. It is important to keep in mind that fixed inlet doesn't always mean Mach 2 limitation.
F-8U-3 can reach Mach 2.9 with fixed inlet

Impressive
The intakes in the Su-57 are variable, similar to known 2D ones but with 3D inclination and LO design. You can check it out here together with a compared analysis vs. that of the F-22:

findpatent.ru/patent/247/2472956.html
Furthermore, there are many other possible limitations such as canopy, structure, coating. Just because the composition of inlet and engine can let you fly faster than a particular speed, doesn't mean there isn't any others factor limit you to velocity below that. For example, DSI inlet and F-135 engine can generate enough thrust to allow F-35 fly faster than Mach 1.6 but it is still limited to Mach 1.6

Certainly this is many times the case. The argumentation in the patent is clearly related to speed but still real performance is largely unknown. I would simpy not be surprised if it turned out to be faster than expected, many design features are in line with that.
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Unread post14 Sep 2019, 19:34

Something I need to point out:

According to Russian Bureau of Intellectual Properties, the thrust vectoring of Su-57 is still 2D (moving along a V trail) instead of 3D.
T-50 2d tvc.jpg

T50 tvc.jpg


Now we know F-22 can deflect 20 deg while Su-57 can deflect 15 deg.
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