R-27ER tailchase chaff issue

When chasing a target with enough speed difference to have a solid radar lock and firing a R-27ER at that target, there is a high chance that the R-27ER will stop tracking completely and fly straight if that target deploys very few chaffs.

The R-27ER is not even turning into the chaff, so it is different than the chaff mechanism when the target is notching. The R-27ER will simply stop guiding and fly straight instead of maneuvering towards the target.

In the following example, the first R-27ER is defeated with a handfull of chaffs. The second R-27ER loses the target to a single old chaff that was dropped long before and dissapeared 3 seconds after the missile launch. Only the third missile is able to hit.

When the target deploys chaffs in a regular interval it is able to defeat any incoming R-27ER in a tailchase scenario.

This does not make any sense. The chaff should be filtered out by the notch filter, and the chaff is not a solid object. The reflective elements of the chaff have enough room for radiation from the target to pass through, so the missile should not have any issues hitting the target.

This seems like an issue with the lift coeff more than it is a guidance issue

But I would still like EDs explanation on this one

https://streamable.com/elvvg

Chizh said that this is how they want the ER to behave in a direct tailchase. He sais that the chaff will form a solid screen which the seeker can not see through. I find this very hard to believe, as the chaff is a bunch of floating particles that will spread out and not form a solid wall.

In your case it also looks like it was chaffed, as it flies right through it. Check the moment when the missiles pulls g the last time. This is just ridiculous.

ED obviously thinks that the R-27 is made by monkeys. All the ER does in DCS is keeping the bandit busy until you are in close range for a R-73 shot. If the blue guys knew how bad the ER really is they would not turn cold on every launch warning and stay much more aggressive.

The main problem in DCS is that AA missiles are all under different standard and some effects apply to some but not to others... there isn't a standard set of rules and then it all feels a lot random.

As for the R-27, it was developed by the same guys at the same time as R-73, think about it.

Chizh said that this is how they want the ER to behave in a direct tailchase. He sais that the chaff will form a solid screen which the seeker can not see through. I find this very hard to believe, as the chaff is a bunch of floating particles that will spread out and not form a solid wall.

 

In your case it also looks like it was chaffed, as it flies right through it. Check the moment when the missiles pulls g the last time. This is just ridiculous.

 

ED obviously thinks that the R-27 is made by monkeys. All the ER does in DCS is keeping the bandit busy until you are in close range for a R-73 shot. If the blue guys knew how bad the ER really is they would not turn cold on every launch warning and stay much more aggressive.

I have no problem with Chizh's explanation, if that puny AMRAAM's radar is affected the same. Is it ?

Chizh said that this is how they want the ER to behave in a direct tailchase. He sais that the chaff will form a solid screen which the seeker can not see through. I find this very hard to believe, as the chaff is a bunch of floating particles that will spread out and not form a solid wall.

The question isn't whether the chaff forms a physical solid wall (which is entirely unrelated to how an object reflects radio waves). The question is whether the radar reflection off the chaff will saturate the seeker and appear to be a wall of uniform reflections.

A similar thing happens with camera CCDs. Sometimes the object one is pointing at is so bright that the CCD forms artefacts while it tries to read the image, like this:

A radar seeker is different from a camera CCD, but the principle is the same. If you point some type of detector or camera at something really bright (either a star like in the above image, or a bunch of material designed to reflect radio emission like a chaff), the detector, whether it be a CCD or missile seeker, might be blinded.

edit: this exact effect is replicated LANTIRN screen of the DCS Tomcat for example

I'm not saying that this is how the R-27, AMRAAM or what have you work, just that it makes no sense to say that "chaff don't form physical walls" like you're saying.

It's kind of funny how the one missile that actually has chaff directly launched against it is the only one that hits. :D

The main problem in DCS is that AA missiles are all under different standard and some effects apply to some but not to others... there isn't a standard set of rules and then it all feels a lot random.

You can defeat an Aim-120 in DCS the same way, but you need all your chaffs and not just 1-3.

The missiles seeker will also have a much stronger radar return from the ground than from the target when fighting in a look down situation. Still it is able to tell what is target and what not by the doppler shift (depending on the aspect).

Compared to a CCD array the radar has additional information to work with (phase, frequency, delay etc.)

Chizh said that this is how they want the ER to behave in a direct tailchase. He sais that the chaff will form a solid screen which the seeker can not see through. I find this very hard to believe, as the chaff is a bunch of floating particles that will spread out and not form a solid wall.

They are a cloud of floating particles, true. But they are a cloud of EXTREMELY REFLECTIVE floating particles. When the return from that cloud gets back to your radar's receiver, it likely saturates the electronics. An analogy to this would be what happens if you shine a bright light in your eyes: You end up with a blotch in your vision that takes time to fade. Likewise, a saturated receiver takes time to desaturate.

Now, this desaturation time is measured in fractions of a millisecond, however radar pulses move even faster. So it is entirely possible for the return pulse from the aircraft behind the cloud to reach the receiver while it is still desaturating. And unless the return is strong enough to 'spike' higher than the declining saturation output in the receiver, the receiver will likely not see the aircraft.

Same thing goes for AIM7 since the beginning. And after the latest update. AIM7 are too easily chaffed to a point that they are not useful any more.

This would mean that whenever a chaff is deployed the seeker is blind, not just in a rear aspect chase. Almost similar to using flares vs. IR missiles.

Radars use notch filters to remove the unwanted reflection from reflectors with no radial closure speed (ground, chaff). Any return within that frequency band will be attenuated, so the seeker is not blinded.

Same thing goes for AIM7 since the beginning. And after the latest update. AIM7 are too easily chaffed to a point that they are not useful any more.

Aim-7 were broken before the last update and were 100% chaff imune (Except for the F14 Aim-7 that used the old Aim-7 model). Now they go for chaff again.

Aim-7M has the same value as the R-27 for chaff resistance, while the Aim-7F is worse and the Aim-7MH is better.

Chizh said that this is how they want the ER to behave in a direct tailchase. He sais that the chaff will form a solid screen which the seeker can not see through. I find this very hard to believe, as the chaff is a bunch of floating particles that will spread out and not form a solid wall.

chaff DOES create a solid wall. the radar cant see through because it jams itself and resolution is not high enough.

The chaff is not solid object but constantly variable wall... reflecting signal back and around, to both ways....

and chaff scatters in seconds to tens of meters area, soon much larger area and it will block all radar in that area trough for hours. In time its effects lower, but only at close, while visible to far distances clearly.

You do not release chaff unless your life depends from it, as you saturate air impenetrableby radars on all parties...

Then it would be nice if the active missiles would behave similar and not require magnitudes more chaff than SARH.

The active missile emits its radiation closer to the chaff, so the ratio of the amplitude of chaff return/target return is even worse.

Then it would be nice if the active missiles would behave similar and not require magnitudes more chaff than SARH.

 

The active missile emits its radiation closer to the chaff, so the ratio of the amplitude of chaff return/target return is even worse.

Yes, the radar missiles will have the exact same problem. But they do have a one huge advantage, the guiding radar possibility to transfer through datalink the true target position if the guiding platform radar can see pass the chaff. As then if example the guiding radar can tell to missile that target is a 5+x km further and missile sees a chaff at 5 km range, then it knows that it needs to fly through.

But that is another question that what does the chaff really do for the seeker, like they do have their own chaff rejection algorithms, but they are not capable to see through it. So example active missile might know to reject the chaff and fly through it and then start to search pattern to find a target but this time it is in (IIRC) a MADDOG mode as it can't by any means know that target it finds is the original target or not. But same thing is that chaff is there to not attract the missile to fly at it, but as well to blind what is otherside of it.

So the most effective way to avoid missile lock is to get chaff between you and the radar (missile or guiding) so it breaks the lock.

The F/A-18C was the first module in DCS to simulate the radar beam. Meaning that there is actual beam Field of View that is moved in front of the aircraft in correct arc degree and speed and bars etc. But AFAIK there is nothing of that in the missiles itself. especially the active missiles.

Meaning that the missile seekers do not have anykind search modes, no FOV, no limitations... nothing. So if you are in the whole arc of the missile seeker gimbal limits and you are anywhere inside the maximum radar range, it can find you instantly without any problems.

While in reality the missiles, especially the active missiles, should have own logic in their radar search patterns, their gimbal speeds, the behavior etc. As those currently find instantly the targets and goes after that.

Every chaff is exactly like a flare, but made only for radar missiles. Meaning that the chaff lifetime was a few seconds, and IIRC what Heatblur developer told, the chaff lifetime was like 4 seconds or so, after that it disappears and it is not anymore calculated by random generator that does missile seek to it or not.

What ED should do, is to make the chaff scatter quickly to wider area, based as well to the new fluid dynamics that are used to do wake turbulence.

So when you release chaff, it ain't a small cloud as it gets fired out and it scatters quickly by wake turbulence to larger area and parts of it will drag along with your aircraft, scattering to larger area.

Each fiber is reflective at different strenghts based its angle to the radar, and there are thousands of those rotating quickly around at various distances and speeds, generating to radar a multiple different speeds and much larger target.

One of the effective ways to missile avoid chaff is that it detects that target suddenly grows larger, the main mass speed changes and then something else continues from it, and that is likely the target that has just chaffed and missile might return to that target. But again, missiles seekers are small, they have narrow FOV as well and they need to do complex search patterns and logics to find a actual target after it leaves the chaff cloud.

But if the target is in the notch and chaffs, that chaff is generating huge amount of speed variations and it is big target, there is no way that any missile can avoid that chaff as there is nothing else there to go.

Now if DCS would start to simulate the chaff clouds (volumetric new cloud system used for that?!) that extends by scattering around, moves by the wind and gets effected by the moisture etc, we would start to see far more realistic radar operations from the chaff point of view as you would not want to release chaff when there are friendlies going to launch missiles at the enemy near you, as you are there just causing trouble for everyone as their radars would be jammed by themselves in that direction.

So when you release a chaff between you and the radar, or you and between the SARH missile it will effectively break the lock and block the radar emissions. So turning and burning while SARH is after you and releasing chaff between is extremely effective way, but not so much in DCS if the missile seeker logic is not there.

But now the Chaff is consider liked Flare, so once you pop out chaff/flare, a random lucky generator is rolled and checked once per second that does the missile seeker lock on to it or not. And various different missiles has a different change to lock on the flare/chaff, and if so happens, the missile turns at it and flies at it.

And if you chaff/flare multiple times, you are just throwing multiple coins up in the air with higher change that the missile checks "LOCK" and guides to the chaff/flare. Why it works so effectively that you just dump those out without any mattering of the order, direction etc.

The R-27 family is well known to eat chaff, even when the chaff is well outside of the guiding radar beam, far far further distance than the target or so, the R-27 just checks all the chaff possibilities in its whole gimbal limits arch and if there is one lucky one (high change) then it will lock to it and game is over from that missile.

There is still a reason why modern fighters has chaff and flares, because they ain't obsolete counter measurements even against most modern missiles and radars.

They are a cloud of floating particles, true. But they are a cloud of EXTREMELY REFLECTIVE floating particles. When the return from that cloud gets back to your radar's receiver, it likely saturates the electronics. An analogy to this would be what happens if you shine a bright light in your eyes: You end up with a blotch in your vision that takes time to fade. Likewise, a saturated receiver takes time to desaturate.

The better analogy is like you get a hundreds of small targets at various speeds, headings etc all at once, quickly enlarging and still moving by the wake turbulence (and later by the wind) between you and the target.

The missile seeker beamwidth is still narrow, it is not a 120 or 90 degree or even 30 degree, but narrow one.

Someone who knows better can tell the beam width, like with a IR missiles that is about 1.5-2 degrees IIRC depending the missile types. So the missile is there just trying to stay on the target by looking it through a straw. And once you manage to lure that straw area to be looking something else for a moment, it will lose you. And if you manage to get out of the last known vector and speed, that the missile seeker is using to require you, it would need to perform a complex search pattern quickly in the possible area where you could be. And if you manage to release multiple flares and chaff at good timing, you force the missile seeker to spend lots of time to determine on each counter measurement that is it the correct target or not. And it needs to decide to either keep flying straight, to previous intercept point or to determine that the new acquired target is the real target and alter the heading to it.

Now, this desaturation time is measured in fractions of a millisecond, however radar pulses move even faster. So it is entirely possible for the return pulse from the aircraft behind the cloud to reach the receiver while it is still desaturating. And unless the return is strong enough to 'spike' higher than the declining saturation output in the receiver, the receiver will likely not see the aircraft.

If there is a chaff cloud between radar and target, then the radar emission needs to first go through the chaff, from where most of the energy is reflected back and causing huge amount of noise and false returns (jamming) at various speed and directions. Then the energy that got through is scattered, weakened and again bounced from different directions from the chaff as well, needs to hit the target and reflect back. Now the energy that is coming back toward missile, needs to again go through the chaff that is reflecting it, changing speed, distances etc and all that energy that from it and through it manages to get toward the missile seeker, needs to be possible analyzed and used to calculate the target vector and speed.

It is like trying to find out what your friend is trying to say, through a two foreign persons relaying the messages and each of them is trying to lie what they hear but still stay in topic.

If the missile is smart enough, it will simply fly through a such jamming and then initiate a search pattern after the chaff. But then the signal can be so weak that it can't detect it or missile is already flying to wrong direction.

The best analogy is to make Aim-120B/C to react more to chaff then they are doing now, its like Aim-120B/C have better radar and chaff rejection then Su-27 radar from 10km in DCS witch I dont believe is the case in RL.

Yes, the radar missiles will have the exact same problem. But they do have a one huge advantage, the guiding radar possibility to transfer through datalink the true target position if the guiding platform radar can see pass the chaff. As then if example the guiding radar can tell to missile that target is a 5+x km further and missile sees a chaff at 5 km range, then it knows that it needs to fly through.

 

But that is another question that what does the chaff really do for the seeker, like they do have their own chaff rejection algorithms, but they are not capable to see through it. So example active missile might know to reject the chaff and fly through it and then start to search pattern to find a target but this time it is in (IIRC) a MADDOG mode as it can't by any means know that target it finds is the original target or not. But same thing is that chaff is there to not attract the missile to fly at it, but as well to blind what is otherside of it.

So the most effective way to avoid missile lock is to get chaff between you and the radar (missile or guiding) so it breaks the lock.

 

The F/A-18C was the first module in DCS to simulate the radar beam. Meaning that there is actual beam Field of View that is moved in front of the aircraft in correct arc degree and speed and bars etc. But AFAIK there is nothing of that in the missiles itself. especially the active missiles.

 

Meaning that the missile seekers do not have anykind search modes, no FOV, no limitations... nothing. So if you are in the whole arc of the missile seeker gimbal limits and you are anywhere inside the maximum radar range, it can find you instantly without any problems.

 

While in reality the missiles, especially the active missiles, should have own logic in their radar search patterns, their gimbal speeds, the behavior etc. As those currently find instantly the targets and goes after that.

 

Every chaff is exactly like a flare, but made only for radar missiles. Meaning that the chaff lifetime was a few seconds, and IIRC what Heatblur developer told, the chaff lifetime was like 4 seconds or so, after that it disappears and it is not anymore calculated by random generator that does missile seek to it or not.

 

What ED should do, is to make the chaff scatter quickly to wider area, based as well to the new fluid dynamics that are used to do wake turbulence.

 

So when you release chaff, it ain't a small cloud as it gets fired out and it scatters quickly by wake turbulence to larger area and parts of it will drag along with your aircraft, scattering to larger area.

 

Each fiber is reflective at different strenghts based its angle to the radar, and there are thousands of those rotating quickly around at various distances and speeds, generating to radar a multiple different speeds and much larger target.

 

One of the effective ways to missile avoid chaff is that it detects that target suddenly grows larger, the main mass speed changes and then something else continues from it, and that is likely the target that has just chaffed and missile might return to that target. But again, missiles seekers are small, they have narrow FOV as well and they need to do complex search patterns and logics to find a actual target after it leaves the chaff cloud.

 

But if the target is in the notch and chaffs, that chaff is generating huge amount of speed variations and it is big target, there is no way that any missile can avoid that chaff as there is nothing else there to go.

 

 

Now if DCS would start to simulate the chaff clouds (volumetric new cloud system used for that?!) that extends by scattering around, moves by the wind and gets effected by the moisture etc, we would start to see far more realistic radar operations from the chaff point of view as you would not want to release chaff when there are friendlies going to launch missiles at the enemy near you, as you are there just causing trouble for everyone as their radars would be jammed by themselves in that direction.

 

So when you release a chaff between you and the radar, or you and between the SARH missile it will effectively break the lock and block the radar emissions. So turning and burning while SARH is after you and releasing chaff between is extremely effective way, but not so much in DCS if the missile seeker logic is not there.

 

But now the Chaff is consider liked Flare, so once you pop out chaff/flare, a random lucky generator is rolled and checked once per second that does the missile seeker lock on to it or not. And various different missiles has a different change to lock on the flare/chaff, and if so happens, the missile turns at it and flies at it.

And if you chaff/flare multiple times, you are just throwing multiple coins up in the air with higher change that the missile checks "LOCK" and guides to the chaff/flare. Why it works so effectively that you just dump those out without any mattering of the order, direction etc.

 

The R-27 family is well known to eat chaff, even when the chaff is well outside of the guiding radar beam, far far further distance than the target or so, the R-27 just checks all the chaff possibilities in its whole gimbal limits arch and if there is one lucky one (high change) then it will lock to it and game is over from that missile.

 

There is still a reason why modern fighters has chaff and flares, because they ain't obsolete counter measurements even against most modern missiles and radars.

ER-27 is guided by DL as well.

I understand how chaff can have quite the affect on a pulse radar regardless of aspect but shouldn't a PD radar be able to better filter out small amounts of chaff in regards to perfectly hot or cold bandits as in shouldn't there be enough contrast in the seeker/radars perspective between CMs and the target for it to guide or is that simply not the case?

Yes. but it's possible that the radar returns from the chaff will be strong enough to keep the radar from detecting any targets behind them.

Same thing goes for AIM7 since the beginning. And after the latest update. AIM7 are too easily chaffed to a point that they are not useful any more.

Welcome to ER-27 world for 4 years now!

I'm 100% sure AIM7 as today, has exactly the same behavior as you described in your tacview.

Yes it does currently, but it enjoyed complete chaff immunity for a long time in between.

For the russian side the R-27 is the main weapon, while the blue jets take Aim-120 99% of the time. Aim-120 can be defeated the same way, but you need significantly more chaff (40+).

How can this Aim-120 track my aircraft movement through 30 walls of chaff?

You also need to consider Fox1 only setting where features only sparrow vs R27 and 530D. I rarely bring any chaff with me as I mainly practiced against other AIM7s within squadron. but thanks to your thread you made me realized that chaff can be very useful also in fox1 settings.

Of course, chaff are far more effective against SARH than the ARH missiles in DCS in any situation.