Operational Performance Comparison: Viper, Beagle and Stubby

The F-35 compared with other modern jets.
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by optimist » 08 Sep 2019, 04:35

southerncross wrote:@eloise:

Bottom line: if we stick to 1 vs 1 analysis we get a much clearer picture than if we throw in the mix every other potential assets, scenario, theater and tactic possible. IMHO this leads to a much better quality discussion overall.


I would say 1vs1 is fun on forums. In the real world it's system vs system and platform specs are secondary, even for the f-35.
Europe's fighters been decided. Not a Eurocanard, it's the F-35 (or insert derogatory term) Count the European countries with it.


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by charlielima223 » 08 Sep 2019, 09:38

marsavian wrote:
The inlets of Typhoon sweep upwards and the engine face is on a higher plane so very little of the face is exposed head on. It also has higher composite composition as well as able to retract its fuel boom which the Rafale designers seemed to have forgot and which will cause RCS problems. BAE said on release its RCS was second only to F-22 and have quoted detection figures in the past vs F-35 which suggested a sub 0.1 sq m RCS.

Look at the sideways profile of the Typhoon, it's obvious the inlets are directly inline with the wings, the upper part with the rear and lower part with all, not the engines whereas Rafale inlet is directly inline with its engine


First, BAE's claim that the Typhoon's RCS is "second only to the the F-22" is pure advertisement fluff.
Second the Rafale's air intake inlet is serpentine in design... perhaps more so than the Typhoons...

Image

Image


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by ricnunes » 08 Sep 2019, 13:15

charlielima223 wrote:
marsavian wrote:
The inlets of Typhoon sweep upwards and the engine face is on a higher plane so very little of the face is exposed head on. It also has higher composite composition as well as able to retract its fuel boom which the Rafale designers seemed to have forgot and which will cause RCS problems. BAE said on release its RCS was second only to F-22 and have quoted detection figures in the past vs F-35 which suggested a sub 0.1 sq m RCS.

Look at the sideways profile of the Typhoon, it's obvious the inlets are directly inline with the wings, the upper part with the rear and lower part with all, not the engines whereas Rafale inlet is directly inline with its engine


First, BAE's claim that the Typhoon's RCS is "second only to the the F-22" is pure advertisement fluff.
Second the Rafale's air intake inlet is serpentine in design... perhaps more so than the Typhoons...

Image



Yes, I fully agree the claim that the Typhoon's RCS is "second only to the the F-22" is a bold overstatement and above all propaganda/advertising BS (or at best it's a statement based on very old info), specially when you have aircraft among the 4.5th gen like the Super Hornet which apparently have far more extensive RCS reduction measures compared to the Typhoon.
Like I previously said in several posts around these forums, I strongly believe and bet that the best 4.5 gen fighter aircraft in terms of RCS is the Super Hornet which is second only to the F-22 and F-35 when it comes to western fighter aircraft.

Regarding the comparison between the Rafale and Typhoon in terms of RCS, I can see another advantage on the Rafale's side, which is the usage of sawtooth edges/surfaces such as the one that can clearly be seen in the picture above posted by charlielima223 (and which I quoted above). The Typhoon doesn't seem to have any of these kind of surfaces and they should be vital for any aircraft intended to have a low RCS - just look at any "pure stealth" aircraft like the F-22, F-35, B-2 and the retired F-117, they all have sawtooth edges/surfaces! I believe this tells us alot.

On the other hand I also agree with marsavian's assessment regarding the non-retractable refuel boom. Some here say that the RCS of the Rafale's non-retractable refuel boom shouldn't be very high but nonetheless it should increase the Rafale's RCS somehow.
With all of this in mind and according to my beliefs, I would rank the 4.5th gen fighter aircraft in terms of having the lowest to higher RCS, the following way:
1- Super Hornet
2- Rafale
3- Typhoon
“Active stealth” is what the ignorant nay sayers call EW and pretend like it’s new.


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by mixelflick » 08 Sep 2019, 14:00

And where would you put Russian birds?

SU-57
SU-35
Mig-35
SU-30SM
SU-27SM2/3

As a reference point, Russians claim SU-35 has a RCS 1/3 of that of the SU-27. That may be so, but I don't think it approaches a SH. Both will further be degraded by external stores, and those Russian AAM's have some big honking fins on them. The R-77 looks to be much better in this respect, but still likely having a higher RCS vs. the AMRAAM..


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by zero-one » 08 Sep 2019, 15:28

optimist wrote:I would say 1vs1 is fun on forums. In the real world it's system vs system and platform specs are secondary, even for the f-35.


The point of having a 1 v 1 or platform vs platform discussion is to see how reliant or less reliant 1 platform will be in a real world scenario.

I.E.
To strike a heavily protected target
Package 1:
F-15C for CAP
F-15E for Strike
F-16CJ for SEAD
E-3 for AEWAC
plus jamming pods etc.

Package 2:
F-35s

Both packages may achieve similar results. but one is heavily reliant on other assets while the other is self supporting.
And these thing happen in real life as well. You won't always have all the support you need from other assets.

A common argument of 4th gen proponents is that upgraded 4th gens can be every bit as effective as 5th gens if placed in the right system. But the problem is they are also too dependent on that system.


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by doge » 08 Sep 2019, 17:08

mixelflick wrote:As a reference point, Russians claim SU-35 has a RCS 1/3 of that of the SU-27.

I found a photo on Wikipedia where I can see the inside of the intake of Su-35S. 8)
https://commons.wikimedia.org/wiki/File ... g_gear.jpg
Similarly, I also found a photo where I can see the inside of the rear of the engine. (If adjust the contrast, it will appear faint.)
https://commons.wikimedia.org/wiki/File ... 013_06.jpg
Attachments
Su-35S intake.jpg


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by southerncross » 08 Sep 2019, 17:54

sprstdlyscottsmn wrote:This is a big culprit.

Ok I see. I wonder how MiG-31 with such big wing loading overcomes this issue to be honest.
Also, an engine may make proportionally less thrust as it enters the turbine section the "same" as drag, but the turbine section has to extract a fixed value of power...

Interesting. I would assume the compressor perceives less resistance from the less dense air, but probably it needs to turn faster too, in order to compensate for the lack of oxygen, so it is not clear to me what weights more at what concrete altitudes. I understand you were simplifying though, and it is clear that from some point onwards there is simply not enough air for the engine to operate properly, no matter how much effort the compressor does, but I don't know if this is due to excess temperature or pure lack of mass flow.
optimist wrote:I would say 1vs1 is fun on forums. In the real world it's system vs system and platform specs are secondary, even for the f-35.

Yes of course. But it is also very difficult to analyse the resulting complexity, so that the discussions addressing it are frequently just going nowhere. This thread's approach is IMHO a right way to tackle complexity, by decomposing the problem in its elementary parts.
garrya wrote:Mig-31 is very fast, at Mach 2.5 cruising speed, it is significantly faster than F-22 and Su-57 at Mach 1.8. Lift is proportional to square of velocity so the faster you fly, the more lift you can generate.

IIRC it cruises 2.35 M, but in any case faster than any other plane that I know. I have never managed to get 100% confirmation on whether this is without AB, or just the plane has so much fuel inside that it can allow itself to keep it engaged for extended periods of time. Having said that, the recent upgrades allow it to fly 2.83 M for "unlimited" time (that is, until fuel runs out, which at that speed will not take very long), so it may be argued that it could dash even faster before attacking a target. The D-30F6 does not seem especially devised for supercruise in any way, with 93 kN dry / 152 kN AB it is just marginally more powerful than other 4th gen fighter engines, and its BPR is 0.57 if I am not wrong, so it would be remarkable for such a big plane, with such high wing loading to cruise at that speed with only that dry thrust... aero is of course purpose-designed for that flight regime, but anyway it seems quite extreme a difference comparing with other planes.
Moreover, pilot in aircraft fly above 50k feet will need pressure suit. It is obvious that Mig-31 pilot have different flight suit from Su-57 or F-22 pilot

Good point. I have seen MiG-31 pilots also with the standard suit, I guess it depends on the mission. I wonder if F-22 / Su-57 pilots do not have similar suits available, otherwise the planes should not be cleared for 65k and more. High altitude flight was indeed a design goal in both of them, I guess it was not for some odd zoom climb only?
is important to remember that service ceiling is not where fighter cruise, rather it is the maximum usable altitude of an aircraft where the margin to stall is only 1.5 G

Yes, I am aware both are different, only I don't know by what margin or rather, how operational cruise altitude is established for each plane. And hence, what aero/ engine constraints are responsible for F-22 for instance not being capable of flying similarly fast and high, with much higher TWR and lower wind load. Maybe design for high maenouverability at lower speeds and altitudes creates too much drag or just the fuel is not enough for such operation modes? In any case, we saw that at 20 km the MiG-25 does not have much more lift margin than those 1.5 g unless flying really fast isn't it?
Also I wonder if all this applies to Su-57 in the same way. From its design elements I would say it may be less restricted for high altitude flight, with big, variable intakes that should feed the engines better than the fixed ones on the F-22. I also think the LEVCONS should be of help to get high lift for turning while being retractable when low drag is needed. Just theorizing but still reasonable IMO.
The measured value of AGM-86 is 100-500 times smaller than your estimated value for AIM-120. That is a big gap in warning time.

What I am seeing in your diagram would point rather to 10-50 times less than the values I saw, it is a lot in any case. The AMRAAM needs an X-band transparent radome, I don't know how the AGM-86 is built. In any case the point was that the detection range, in any of the discussed scenarios, was more than those 11 or 5 nm for the MAWS warning. From a realistic point of view, it would be interesting to know what the Zaslon-AM detection range would be, if cued by other elements of the AD.

BTW, I will post a bit more of info about your MiG-25 diagrams later on.


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by garrya » 09 Sep 2019, 03:33

southerncross wrote:Ok I see. I wonder how MiG-31 with such big wing loading overcomes this issue to be honest

By flying very fast

southerncross wrote:Good point. I have seen MiG-31 pilots also with the standard suit, I guess it depends on the mission. I wonder if F-22 / Su-57 pilots do not have similar suits available, otherwise the planes should not be cleared for 65k and more. High altitude flight was indeed a design goal in both of them, I guess it was not for some odd zoom climb only?
Yes, I am aware both are different, only I don't know by what margin or rather, how operational cruise altitude is established for each plane. And hence, what aero/ engine constraints are responsible for F-22 for instance not being capable of flying similarly fast and high, with much higher TWR and lower wind load. Maybe design for high maenouverability at lower speeds and altitudes creates too much drag or just the fuel is not enough for such operation modes? In any case, we saw that at 20 km the MiG-25 does not have much more lift margin than those 1.5 g unless flying really fast isn't it?
Also I wonder if all this applies to Su-57 in the same way. From its design elements I would say it may be less restricted for high altitude flight, with big, variable intakes that should feed the engines better than the fixed ones on the F-22. I also think the LEVCONS should be of help to get high lift for turning while being retractable when low drag is needed. Just theorizing but still reasonable IMO.

It is possible to climb above 50k ft for a few minutes without a pressure suit but it is often deemed very dangerous.
LEVCONS is basically a close coupled canard that is more optimized for stealth IMHO. I don't think it help much for high altitude flying.
Altitude constraint for F-22, Su-57 should be similar to F-15, Su-27

southerncross wrote:What I am seeing in your diagram would point rather to 10-50 times less than the values I saw, it is a lot in any case. The AMRAAM needs an X-band transparent radome, I don't know how the AGM-86 is built. In any case the point was that the detection range, in any of the discussed scenarios, was more than those 11 or 5 nm for the MAWS warning. From a realistic point of view, it would be interesting to know what the Zaslon-AM detection range would be, if cued by other elements of the AD.

0.5/0.001 = 500 times.
But I understand your PoV. Zaslon-M can detect AMRAAM from 30 km if we assume AMRAAM's RCS is above clutter rejection threshold.
0E4A19E4-C727-47C0-B9F4-D21002343089.png
0E4A19E4-C727-47C0-B9F4-D21002343089.png (238.3 KiB) Viewed 24106 times

AMRAAM velocity at that altitude is Mach 4
Mig-31 cruising velocity is Mach 2.5
Total closure rate is Mach 6.5


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by Corsair1963 » 09 Sep 2019, 04:16

doge wrote:
mixelflick wrote:As a reference point, Russians claim SU-35 has a RCS 1/3 of that of the SU-27.

I found a photo on Wikipedia where I can see the inside of the intake of Su-35S. 8)
https://commons.wikimedia.org/wiki/File ... g_gear.jpg
Similarly, I also found a photo where I can see the inside of the rear of the engine. (If adjust the contrast, it will appear faint.)
https://commons.wikimedia.org/wiki/File ... 013_06.jpg



A third of a Brick is still a Brick.... :shock:


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by marsavian » 09 Sep 2019, 16:30

The Russians are claiming more like a tenth than a third.


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by southerncross » 09 Sep 2019, 21:31

garrya wrote:By flying very fast

True, that makes it questionable that it can be done without AB.
LEVCONS is basically a close coupled canard that is more optimized for stealth IMHO. I don't think it help much for high altitude flying.

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.
Altitude constraint for F-22, Su-57 should be similar to F-15, Su-27

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.
0.5/0.001 = 500 times.

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.
But I understand your PoV. Zaslon-M can detect AMRAAM from 30 km if we assume AMRAAM's RCS is above clutter rejection threshold.

Fair enough. The missile should come from above in a long range shot, that should help reduce clutter, but still we don't really know what is ultimately possible. If cued by someone else, threshold could be lowered and range increased.
AMRAAM velocity at that altitude is Mach 4
Mig-31 cruising velocity is Mach 2.5
Total closure rate is Mach 6.5

Depending on the launch conditions, but ok. What is the point, that Zaslon may not be capable of handling the target? It may be the case but is not clear to me from what I have read (target speed up to 6 M). The need to handle targets at that speed is rather important, but I don't know what the performance of the AM version is with its improved processors vs. Zaslon-M. MiG-31 has among its missions to intercept high-speed missiles and has done so in drills.

As to the diagrams, I just managed to get some bits of info here and there, without big surprises compared to what Spurts already explained.

First is indeed a diagram of CL depending on Mach number for various AoA, referred to MiG-25RB and PU.
Circles and triangles seem to indicate some testing. The two curves on the top marked Cy appear to relate to activation and deactivation of some mechanism named "SAU", I don't know if it relates to deployment of flaps. I didn't manage to understand the three descending curves tagged 0/5, 10 and 15 km, there is some indication to max deflection of the stabiliser of 23.5º
Not many comments for the second. The third is overload related to height (H) and weight (G). The lines with crosses apparently refer the plane loaded with 4 x FAB500 bombs and 2 x other weapon I don't know (MBDZ-U-2), the others the plane without external loads.
The fourth is a further overload diagram for a plane mass of 28,000 kg. BTW it seems to indicate that at 2.5 M and 20000 m it can sustain > 2.5 g
The fifth is a nomogram that links Cl in the first quadrant, overload in the second, some lift coefficient I don't understand in the third and altitude in the fourth. I would need to research and understand this in English first to be honest...
The sixth is again overload vs. speed, it includes some explanation about how the AB mode of the engines would take the plane to go beyond is max. overload below 18 km altitude. The seventh is the flight envelope indeed, I had difficulty to translate much from the indications.


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by ricnunes » 09 Sep 2019, 23:02

southerncross wrote:
AMRAAM velocity at that altitude is Mach 4
Mig-31 cruising velocity is Mach 2.5
Total closure rate is Mach 6.5

Depending on the launch conditions, but ok. What is the point, that Zaslon may not be capable of handling the target? It may be the case but is not clear to me from what I have read (target speed up to 6 M).


The point IMO is:
- Even if the Mig-31's Zaslon Radar is for some reason able to detect an incoming AMRAAM at a range of 30km (which I have my doubts!) flying at Mach 4 and the Mig-31 is for example flying at Mach 2.5 at an altitude of 50k ft and resuming with a closure rate of Mach 6.5 then it will take the AMRAAM something 16 seconds to hit the incoming Mig-31 (if my math isn't wrong).
Since the Mig-31 should turn like a brick when flying at Mach 2.5 it won't be able to perform an evasive maneuver by turning away from the missile in a timely manner.

Well, at least that's what I perceive from the situation above.
“Active stealth” is what the ignorant nay sayers call EW and pretend like it’s new.


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by ricnunes » 09 Sep 2019, 23:22

mixelflick wrote:And where would you put Russian birds?

SU-57
SU-35
Mig-35
SU-30SM
SU-27SM2/3

As a reference point, Russians claim SU-35 has a RCS 1/3 of that of the SU-27. That may be so, but I don't think it approaches a SH. Both will further be degraded by external stores, and those Russian AAM's have some big honking fins on them. The R-77 looks to be much better in this respect, but still likely having a higher RCS vs. the AMRAAM..


Well, about your list above I would say that the harder part would be where to put the Mig-35 (among or between the Flanker series aircraft). For that one would need to know how the Mig-29 RCS compares with the Su-27 RCS and then how the Mig-35 RCS compares to the Mig-29. Other than that I would say that your list/order should be pretty much accurate/correct.

I also fully agree with your SH versus Su-35 and external stores assessment in terms of RCS.
“Active stealth” is what the ignorant nay sayers call EW and pretend like it’s new.


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by southerncross » 10 Sep 2019, 11:07

ricnunes wrote:The point IMO is:
- Even if the Mig-31's Zaslon Radar is for some reason able to detect an incoming AMRAAM at a range of 30km (which I have my doubts!) flying at Mach 4 and the Mig-31 is for example flying at Mach 2.5 at an altitude of 50k ft and resuming with a closure rate of Mach 6.5 then it will take the AMRAAM something 16 seconds to hit the incoming Mig-31 (if my math isn't wrong).
Since the Mig-31 should turn like a brick when flying at Mach 2.5 it won't be able to perform an evasive maneuver by turning away from the missile in a timely manner.

Well, at least that's what I perceive from the situation above.

The whole discussion and simulation by Spurts brought the (for me) unexpected result that, even when the MiG-31 indeed turns badly, the AMRAAM is not much better, more even so the higher the encounter takes place, and may end up loosing its sight of the target after some turning. Besides it has by that moment (long range shot) no propulsion, so it depletes its energy fast too, trying to catch the MiG. You can read above in what conditions the attack could succeed or not and what are the uncertainties and assumptions.


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by ricnunes » 10 Sep 2019, 15:02

southerncross wrote:
ricnunes wrote:The point IMO is:
- Even if the Mig-31's Zaslon Radar is for some reason able to detect an incoming AMRAAM at a range of 30km (which I have my doubts!) flying at Mach 4 and the Mig-31 is for example flying at Mach 2.5 at an altitude of 50k ft and resuming with a closure rate of Mach 6.5 then it will take the AMRAAM something 16 seconds to hit the incoming Mig-31 (if my math isn't wrong).
Since the Mig-31 should turn like a brick when flying at Mach 2.5 it won't be able to perform an evasive maneuver by turning away from the missile in a timely manner.

Well, at least that's what I perceive from the situation above.

The whole discussion and simulation by Spurts brought the (for me) unexpected result that, even when the MiG-31 indeed turns badly, the AMRAAM is not much better, more even so the higher the encounter takes place, and may end up loosing its sight of the target after some turning. Besides it has by that moment (long range shot) no propulsion, so it depletes its energy fast too, trying to catch the MiG. You can read above in what conditions the attack could succeed or not and what are the uncertainties and assumptions.


Sure, but one has to be aware that modern missiles like the AMRAAM don't chase the aircraft "per se". They "lead pursuit" which means during the AMRAAM launch and flight that the Mig-31 (or any other aircraft for that matter) is being tracked by the launching's aircraft radar (let's say a F-35 or other aircraft) and communicating (data-link) with the missile which means that the missile won't go directly after the aircraft (Mig-31 in this case) but instead it flies towards the expected point of impact/intercept. This point of impact is always known and updated during the missile's flight path. Having the consideration the separation that the missile starts from the target, all of this means that the missile doesn't have make "sharp" turns and thus it doesn't lose that much energy even when/if the point of impact is constantly updated.
I don't know if I made myself or my point clear 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...
“Active stealth” is what the ignorant nay sayers call EW and pretend like it’s new.


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