Maximum range of R-27ER in DCS

[Ironhand]

Unfortunately, I’m not in a position to check...but doesn’t the Su-27 manual indicate that you should delay launching until the range marker has passed a certain distance below the R-Max mark? I could have sworn I saw it in there somewhere.

[Fri13]

1 hour ago, GGTharos said:

They're quite dependable for telling you that you're being attacked.

 

And LPI radar does shorten dramatically the detection range, it combined with the ARH makes interesting engagement possibilities.

[Cmptohocah]

7 hours ago, dundun92 said:

But what if the bandit pilot sneezes and accidentally moves the control stick half an inch and causes a slight flight patch deviation ? What if the wind changes direction by a little bit? What if you fired it 0.5° off of the ASE circle? What if you rolled a bit during launch, and the time the missile took to correct meant that the missile had to make a slightly larger turn to get onto the target, giving it slightly less energy (assuming the missile does this sort of manuever)? Do you really want to instruct pilots to be firing at a range where something like that trashes the shot? There has to be some sort of margin, even if its not that big, but the question is how much? Until we know that you have to treat DLZ ranges like this as Raero at a minimum, but with potential to be higher.

 

 

I don't think it would be fun to sneeze into an oxygen mask, or God forbid throw up in it :D

But jokes aside, yeah I mean of course they must have used some sort of margin. I think it comes down to what "non-maneuvering" target actually means. I see your point, we are missing this "margin" part. 

 

 

[Cmptohocah]

8 hours ago, Ironhand said:

Unfortunately, I’m not in a position to check...but doesn’t the Su-27 manual indicate that you should delay launching until the range marker has passed a certain distance below the R-Max mark? I could have sworn I saw it in there somewhere.

The reference I found says:

"When firing two missiles (not in a salvo) it is recommended to fire the first one at DRmax1 and the second one at DRmax2. When firing salvo it is recommended to fire at DRMax2." [section 5, page 152]

 

If I am not mistaken, DRmax1 is the RMax value and DRmax2 is the no-escape zone. Also, I don't really speak Russian, but many words are similar to my native language.

[BlackPixxel]

The missile at the max range in the graphs have some speed left in case there is some target maneuvering.

It will certainly not allow for very serious maneuvering of the target, but at least for some.

 

 

If the upper range mark was the absolute aerodynamic range, then the manual would never recommend to fire it at that range, but at a value at least a bit below.

 

 

Think about it, everything about the HUD in the Su-27 is about making target interception simple and almost automated for the pilot.

It automatically prioritizes targets.

It automatically locks the most dangerous target as soon as it gets within weapon engagement range.

Depending on the selected missile the guidance ring will guide the pilot into the most favourable intercept path.

It shows the pilot when to abort the attack if he gets to close, and in which direction he has to pull away from the target.

It only makes sense that the DRmax1 mark shows the pilot a range at which he has a somewhat decent chance to hit the target. A max aerodynamic range will definetly not be a good enough chance.

 

 

 

[GGTharos]

3 hours ago, Cmptohocah said:

The reference I found says:

"When firing two missiles (not in a salvo) it is recommended to fire the first one at DRmax1 and the second one at DRmax2. When firing salvo it is recommended to fire at DRMax2." [section 5, page 152]

 

If I am not mistaken, DRmax1 is the RMax value and DRmax2 is the no-escape zone. Also, I don't really speak Russian, but many words are similar to my native language.

 

The only source that we have for this is the sparrow which specifies something like a 4-5g reserve for 1-3 seconds.  This takes care of a number of things like wind gusts, sensor inaccuracy etc.   This reserve requires different speed depending on altitude (the higher you are, the more speed you need).  Likewise, the radar fuze needs a certain amount of closure to function which shortens rear aspect range a bit.

[Ironhand]

5 hours ago, Cmptohocah said:

The reference I found says:

"When firing two missiles (not in a salvo) it is recommended to fire the first one at DRmax1 and the second one at DRmax2. When firing salvo it is recommended to fire at DRMax2." [section 5, page 152]

 

If I am not mistaken, DRmax1 is the RMax value and DRmax2 is the no-escape zone. Also, I don't really speak Russian, but many words are similar to my native language.

 

I had a few minutes to check but couldn't find the reference I was looking for. However, I did find the reference that was making me think that DRmax1 was max range against a non-maneuvering target:

 

Quote

5.1.7. Special operating features of the Armament Control System during complete (ППО) and incomplete (НПО) instrument support.

 

The Armament Control System supports the use of guided missiles (УР-Yправляемая Pакета) and the onboard cannon (ВПУ) in the following modes:

 

- Full instrument support (PPO) when both the Radar Aiming Complex and the Optical-Electronic Targeting System have complete data on the parameters required for successfully completing the combat task, in which case the demarcations of the range scale take the following values:

 

    a) 150, 100, 50, 25, 10, and 5 when the Radar Aiming Complex is the master channel;
    b) 100, 50, and 10 when the IRST is the master channel.

 

    When attacking the target in PPO mode, an index (arrow) indicates the current target range on the range scale:

 

            - maximum allowable launch range mark against a target that is certain not to maneuver – R-max1 (ДРмакс1)
            - maximum allowable launch range mark for a target that is certain to maneuver – R-max2 (ДРмакс2)
            - minimum allowable launch range mark – R-min (ДРмин)
 

 

[Cmptohocah]

3 hours ago, Ironhand said:

 

I had a few minutes to check but couldn't find the reference I was looking for. However, I did find the reference that was making me think that DRmax1 was max range against a non-maneuvering target:

 

 

You can find these two range definitions on the page 193. of the Su-27SK manual. It's depicted as point numbered 34 on the HUD scheme (ДРмакс1, ДРмакс2 and ДРмин).

Not really relevant to the topic, but I just realized it: apart from the "A" attack label there are two maneuvering symbols "Г↑", "Г↓" (Gorka) and an afterburner symbol "Ф". I know that a "Gorka" is steep climb/descent maneuver, but I wonder what does it depict here?

Edited January 8, 2021 by Cmptohocah

[GGTharos]

It could be commands from GCI?

[Ironhand]

1 hour ago, Cmptohocah said:

...

Not really relevant to the topic, but I just realized it: apart from the "A" attack label there are two maneuvering symbols "Г↑", "Г↓" (Gorka) and an afterburner symbol "Ф". I know that a "Gorka" is steep climb/descent maneuver, but I wonder what does it depict here?

 

Instructions to climb, descend, use afterburner issued by GCI officer.

 

Edit: GG beat me by a minute. That’s what happens when you’re interrupted by work.

 

Edit 2: Yes, I think page 193 is the reference in my quote.

Edited January 8, 2021 by Ironhand

[Cmptohocah]

5 minutes ago, Ironhand said:

Instructions to climb, descend, use afterburner issued by GCI officer.

Wow, the more I discover real capabilities of the Su-27 the more I realize how much its miss-represented it is in DCS. I always wondered how come it can be called an "air superiority" fighter, but it makes more and more sense. It was basically Soviet Union's answer to the F-15.

 

Also, it seems that the Soviets put the focus on the integrated battlefield way back in the early development. GCI sending info, aircraft-to-aircraft sending info, SAM to aircraft/GCI sending info.

Edited January 8, 2021 by Cmptohocah

[Ironhand]

Yes, the true capabilities as well as the increased pilot workload in a full fidelity Su-27 are somewhat minimized in the FC version.
 

Actually, there’s quite a bit of useful info in that Su-27SK manual. Someday I might actually try fighting according to its dictates.

[Cmptohocah]

16 minutes ago, Ironhand said:

Yes, the true capabilities as well as the increased pilot workload in a full fidelity Su-27 are somewhat minimized in the FC version.
 

Actually, there’s quite a bit of useful info in that Su-27SK manual. Someday I might actually try fighting according to its dictates.

With the current setup is quite simple: "Taxi, takeoff, fire some missiles, get shot down, repeat."

[GGTharos]

And with a full fidelity aircraft it won't be that much different ... unless people are still harboring hopes that it's going to somehow compete with an AMRAAM/other modern ARH platform.  In an 80's type scenario where the opposition is slinging sparrows around and don't use more modern ECM/ECCM that would be quite different.

[Ironhand]

22 minutes ago, Cmptohocah said:

With the current setup is quite simple: "Taxi, takeoff, fire some missiles, get shot down, repeat."

 I stick to opponents I have little trouble winning against—the AI.

Edited January 8, 2021 by Ironhand

[Fri13]

13 hours ago, Cmptohocah said:

 

I think it comes down to what "non-maneuvering" target actually means. I see your point, we are missing this "margin" part.

 

That you do not change the speed, altitude or heading.

You are a steady target with constant speed, altitude and heading.

So target is flying and you lock on radar and launch, in that moment of launch the parameters are for the given expectation.

 

This is why the kinematic max range tables are critical so you know the limitations of the weapon without any other factors in it.

Then you use your knowledge and expectations in the given launch moment that how does that scenario affect to that performance table you know.

 

Like if the target is at 120 km away from you, it is different than it being 60 km from you.

Target is heading hot at you or it is burning straight away from you.

The target behavior and capabilities only you know in that moment are what you need by best of your knowledge and skills apply to the pure weapon performance capabilities.

The engineer designing the weapon can not apply any of those things to the performance tables. It just renders them useless if done so.

 

Like how does the engineer know that target at 50 km range that is heading to you at Mach 1.2 at 12 km altitude will 7 seconds after your missile launch make a split S and is now heading straight away from you at Mach 1.1 at 9.5 km altitude? How would the engineer write down that scenario to that performance chart? What to do if it is 15 seconds instead 7 seconds? What if it is 90 degree turn and not 180 degree? What if the target did drop from Mach 1.2 to 0.7? What if the enemy is so idiotic that it accelerates Mach 1.8 and continues head-on with the missile?

 

That is why pilot needs to know only the kinematic performance of the weapon, as that is their rule book how to release the weapon in given scenario they face. The aircraft weapon system can signal and inform pilot with the kinematic performance limitations as well, but pilot needs to make the decision. Why it is critical that pilot gets target information about altitude, speed and heading, as well the capabilities of the target (what type of it is). That they know their own aircraft parameters too.

 

Air war is pretty much a poker game. As defender you win if you can make other to abort their mission or just deny their access to airspace. No need to hit them with missile or anything. If the missile gets the target drop their loadout to avoid the missile, it is a win. If the missile makes the target abort their attack it is a win.

That missile just likely saved many lives on the ground, and made possible for a whole unit capable to continue fight in required condition.

 

Nothing of that can be written to weapon performance tables. Why you just give the pure data in simple form so the pilot can do their judgement and application for it.

[Fri13]

11 hours ago, BlackPixxel said:

The missile at the max range in the graphs have some speed left in case there is some target maneuvering.

It will certainly not allow for very serious maneuvering of the target, but at least for some.

 

If It is for the missile intercept the target at those parameters on the moment. It could be that it can have that capability intercept 8-9 G target in the last maneuver phase. So the missile is not "it is still capable fly straight and not fall" but it can intercept 900/1100 km/h target pulling =< 8-9 G at 60 km distance.

 

This is so example with SAM systems. Where the intercept tables are for the given target maneuverability. If target flies at 600 m/s then intercept range is shorter and lower (launch is delayed, target is allowed to get closer) and if target flies at 300 m/s then intercept range is longer and higher (launch is advanced, target can fly further). This is with the missile kinematic maneuver capabilities and warhead destructive range. But nothing doesn't deny the missile to fly far further than those, it just requires target parameters to change. As if target is a fighter flying at 850 km/h it is not engaged so far distance as 747 that is flying same parameters, as you know that the fighter has different kinematic capabilities than the 747. So you can launch the missile against 747 from far further distance as it is not going to pull more than 2-3 G if it detects the missile. While fighter pilot has change to detect the launch or detect targeting and pull way more.

 

So example when you read on SAM system data like "range 15 km and altitude 4 km" it is for common target like fighter, pulling the missile capable G's while traveling at given speed like 300/600 m/s. If the target parameters changes worse, then the range and altitude grows as well, so the missile can example intercept a Cessna 172 at 22 km range and 7 km altitude.

 

11 hours ago, BlackPixxel said:

If the upper range mark was the absolute aerodynamic range, then the manual would never recommend to fire it at that range, but at a value at least a bit below.

 

Think about it, everything about the HUD in the Su-27 is about making target interception simple and almost automated for the pilot.

It automatically prioritizes targets.

It automatically locks the most dangerous target as soon as it gets within weapon engagement range.

Depending on the selected missile the guidance ring will guide the pilot into the most favourable intercept path.

It shows the pilot when to abort the attack if he gets to close, and in which direction he has to pull away from the target.

It only makes sense that the DRmax1 mark shows the pilot a range at which he has a somewhat decent chance to hit the target. A max aerodynamic range will definetly not be a good enough chance.

 

Those are good points.

But question is again what is the meaning of "recommendation" as value? As it is not recommended to launch weapon if it can't reach the target, but it is not allowed or impossible, so it is recommendation that if target is further than 60 km it is not launched as it can't intercept it, but you can have effect for the target anyways even if missile can't reach it.

 

[TaxDollarsAtWork]

8 hours ago, GGTharos said:

And with a full fidelity aircraft it won't be that much different ... unless people are still harboring hopes that it's going to somehow compete with an AMRAAM/other modern ARH platform.  In an 80's type scenario where the opposition is slinging sparrows around and don't use more modern ECM/ECCM that would be quite different.

I'm not sure I'd agree with this. The Su-27SK with R-27Es up against Teen series fighters with AIM-9Ms and AIM-120A/Bs and avionics of the 80s and 90s, is still arguably a rather even match up in most context.

 

It does struggle against the noughties MLU types but that's par for the course for legacy avionics and weapons. As countless exercises have proven.

Edited January 9, 2021 by TaxDollarsAtWork

[Cmptohocah]

14 hours ago, GGTharos said:

And with a full fidelity aircraft it won't be that much different ... unless people are still harboring hopes that it's going to somehow compete with an AMRAAM/other modern ARH platform.  In an 80's type scenario where the opposition is slinging sparrows around and don't use more modern ECM/ECCM that would be quite different.

The Su-27 is more than capable of going up against the AMRAAM even in the current setup. Only issue is that the AIM-120 currently has so much better aerodynamics/guidance that it seams nearly impossible to win in this scenario.

One thing that a real Su-27 can do, and the FC one can't, is a cooperative attack. This means that one platform is providing the guidance and the other one is launching the SARH missiles.

[Fri13]

5 hours ago, TaxDollarsAtWork said:

I'm not sure I'd agree with this. The Su-27SK with R-27Es up against Teen series fighters with AIM-9Ms and AIM-120A/Bs and avionics of the 80s and 90s, is still arguably a rather even match up in most context.

I agree.

• If A version in 1991 had max range of 50 km, then R-27R was more than a match for it.
• The B from 1994 added new guidance system so range likely got better, but at least maneuverability did.
• The C from 1996 made missile less capable maneuver than A and B because smaller fins (to fit six inside F-22 instead four), but improved guidance system.
• C4 from 1998 with better fuze to be more capable destroy target.
• C5 for export in 2000 and C6 for USA. Improved fins, radar resolution, guidance and more fuel to increase max range to 105 km because smaller rudder actuators taking less space (RAF received C5 in 2010-2013).
• C7 in 2004 with new electronics made more room for fuel, so max range got to 120 km. USAF received it in 2006.
• C8 aka D from 2006 with requirement for software updates, range to 180 km.

 

https://en.missilery.info/missile/aim120

 

Simply put, most engaments would happen in 2005 against AIM-120B with 50(+) km or C with less capable turning. And few would get C5 with that 105 km maximum range etc.

 

5 hours ago, TaxDollarsAtWork said:

It does struggle against the noughties MLU types but that's par for the course for legacy avionics and weapons. As countless exercises have proven.

 

If we take a more modern Su-27 than SK, it will make up to the R-27E limitations back then. As SARH is more about guiding radar capabilities than own seeker, and AIM-120 has gone multiple major upgrades as guiding radar and software is in the missile.

[GGTharos]

10 hours ago, TaxDollarsAtWork said:

I'm not sure I'd agree with this. The Su-27SK with R-27Es up against Teen series fighters with AIM-9Ms and AIM-120A/Bs and avionics of the 80s and 90s, is still arguably a rather even match up in most context.

 

It does struggle against the noughties MLU types but that's par for the course for legacy avionics and weapons. As countless exercises have proven.

 

The Su-27SK radar is only a decade if not more behind in technology, so are the missiles.  The antennas alone are comparatively old design.  It wasn't even IRL and it shouldn't be even in game.

 

Even if we take the original F-15A as a 'match-up' with its original APG-63, the performance of that radar is better but maybe not egregiously.  Consider that when the flanker entered service, the worst tuned MSIP APG-63 was as good as the best tuned original radar which the flanker was effectively comparable to - and by the time the flanker came around, it wasn't in danger of having to deal with an older APG-63.

 

The expected exchange ratio in the 90s was four to six flankers downed per eagle.  This shrunk a bit as time went on and Su-27's took upgrades, but that's not the flanker that's in-game.

 

Quote

One thing that a real Su-27 can do, and the FC one can't, is a cooperative attack. This means that one platform is providing the guidance and the other one is launching the SARH missiles.

 

 

This turns two weapon platforms into one, and it's not terribly effective anyway - maybe you can think of scenarios where it's all nice in DCS but IRL those two aircraft are going to be able to attack only one target at a time since their radars are tuned to the same channel.  Radars are tuned to different channels to very specifically prevent the sort of interference that this leads to - and there is IRL experience with this sort of thing written up in reports with the sparrow experience in SEA.

 

And FYI, nothing is stopping any SARH carrier from pulling the same trick.   It's not like the flanker is special.

 

In any case, other than a couple of anecdotes, there's no evidence that this is used anywhere as a serious tactic.  SAMs might do it for good reasons, but then SAMs have a lot more options because they don't have to be flown at the same time and you can take over a lot of automation.

 

What you really want is a newer flanker.  The SK is severely out-dated compared to any 90's AMRAAM platform.

 

Of course, none of that is really reflected in DCS (and in particula in FC3), so we probably don't need to worry too much about it.

 

3 hours ago, Fri13 said:

Simply put, most engaments would happen in 2005 against AIM-120B with 50(+) km or C with less capable turning. And few would get C5 with that 105 km maximum range etc.

 

A 120C might be slightly less maneuverable than a 120B, but that really means it just needs to arrive with slightly more speed at the same range.   And besides, will the target be able to tell the difference between a missile pulling 38g and 35g?   My point is just that this 'less maneuverable' thing isn't an issue - it's only academic, not like say an AIM-9D vs an AIM-9M where a highly maneuverable aircraft could take serious advantage of the difference.

 

 

In any case, ED has stated that they will CFD the R-27 ... whenever.   There will be three major outcomes from this:  Longer range, better turning, just as it happened for other missiles.

In addition, the modern autopilot code etc will make the missile fly more efficiently overall, and you'll also see more prox hits (check out the sparrow, it does this now - I see more prox hits from it).

Edited January 9, 2021 by GGTharos

[TaxDollarsAtWork]

1 hour ago, GGTharos said:

 

The Su-27SK radar is only a decade if not more behind in technology, so are the missiles.  The antennas alone are comparatively old design.  It wasn't even IRL and it shouldn't be even in game.

 

Even if we take the original F-15A as a 'match-up' with its original APG-63, the performance of that radar is better but maybe not egregiously.  Consider that when the flanker entered service, the worst tuned MSIP APG-63 was as good as the best tuned original radar which the flanker was effectively comparable to - and by the time the flanker came around, it wasn't in danger of having to deal with an older APG-63.

 

The expected exchange ratio in the 90s was four to six flankers downed per eagle.  This shrunk a bit as time went on and Su-27's took upgrades, but that's not the flanker that's in-game.

I never said it was at a substantial advantage over the Eagle or anything like that, it did though present some trouble for US planers since in many ways it would be trading with enemy aircraft as if it was as good as a contemporary F-16 or F/A-18 being that it was the only Combloc fighter at the time to actually engage in BVR combat with some semblance of parity, the MiG-29s at the time are nothing but ratrod MiG-23s really without any real ability to sustain and contest air control.

 

Posture would play a part in it too, say in a 1990s vietnam or serbia Redux scenario Flankers with R-27Es as DCA could limit the autonomy of strike packages by harassing them with longer range high energy Alamo Slavos forcing the packages to maneuver and reset turning them into mission kills further restricting Package size over the target area.

Given just Russia's obsession with the F-16 one could easily make the case the Early Flankers sole purpose was to greatly limit what ever impact such an important backbone type would have in combat.

 

I think that is worth noting.

[GGTharos]

I agree, which is why I said some of the disadvantages are mitigated with tactics and that we don't really have all this in DCS for multiple reasons.  We also don't have any of the support infrastructure for warfare on either side, ie. intel gathering, comms/radar jamming etc.

[Cmptohocah]

On 1/9/2021 at 4:39 PM, GGTharos said:

This turns two weapon platforms into one, and it's not terribly effective anyway - maybe you can think of scenarios where it's all nice in DCS but IRL those two aircraft are going to be able to attack only one target at a time since their radars are tuned to the same channel.  Radars are tuned to different channels to very specifically prevent the sort of interference that this leads to - and there is IRL experience with this sort of thing written up in reports with the sparrow experience in SEA.

 

And FYI, nothing is stopping any SARH carrier from pulling the same trick.   It's not like the flanker is special.

 

In any case, other than a couple of anecdotes, there's no evidence that this is used anywhere as a serious tactic.  SAMs might do it for good reasons, but then SAMs have a lot more options because they don't have to be flown at the same time and you can take over a lot of automation.

 

It is very important feature in case one of the platforms does not have an operational radar. Also it can be used as a tactical improvement where the forward platform launches the SARH and can turn away, while the rear platform provides guidance.

 

Saying that "there's no evidence that this is used anywhere as a serious tactic" is not really a valid argument, as this does not mean that it's not being used nor that it can't be used.

[GGTharos]

55 minutes ago, Cmptohocah said:

It is very important feature in case one of the platforms does not have an operational radar.

 

It isn't.  You probably cannot even use it that way, the missiles need to tune to the radar channel before launch, and radar channels are pre-set on the ground to avoid interference.  Sure, you could agree on having a mutual channel and tune up your missiles if the opportunity presented itself ... when will it?

 

55 minutes ago, Cmptohocah said:

Also it can be used as a tactical improvement where the forward platform launches the SARH and can turn away, while the rear platform provides guidance.

 

If you're facing a single opponent there's no point in using it, if you're facing multiple opponents you've made a tactical error by leaving the other aircraft free vs your two aircraft.

 

55 minutes ago, Cmptohocah said:

Saying that "there's no evidence that this is used anywhere as a serious tactic" is not really a valid argument, as this does not mean that it's not being used nor that it can't be used.

 

If it isn't valid, why isn't anyone using it?  Why are radars deliberately tuned to avoid this?  IRL isn't some DCS server where you semi-randomly encounter singletons who don't know what they're doing.