R-27R Tracking Issue?

[Cmptohocah]

Could someone please explain to me what is my R-27R tracking instead of the enemy aircraft? Please see the TacView file in the attachment - r27r.zip

Engagement is between Su-27 Flanker (Nix)and A-10C Thunderbolt II (afof).

I fire an R-27R from 4.2km and (with the radar lock, on) it flies in a completely straight line as if I fired an unguided missile instead of a SARH.

After that an R-73 is fired at 14:55:33 server time (track time 00:00:15) and it too decides to chase some ghosts.

 

I realize that the target was beaming, but that should present a lock-on issue, not a tracking one.

Also I have no idea what the R-73 was thinking.

 

Any input is appreciated.

r27r.zip

[Drona]

Not at the home PC to have a look at the tacview, but going off what you said --

 

1. R-27R: Well, the target is beaming.. that's enough for it to be defeated. And the target being an A-10, it was slow and probably in a notch to the radar. Hence, the missile missing.

 

2. For the R-73, were you against the sun? If so, it can miss. Also, was the A-10 flaring or pre-flaring?

[fudabidu]

Your R-27 clearly makes a slight right turn after launch. You probably didn't see it from the cockpit, but it's easy to see with free camera in TAC.

 

At 14:55:32 you can see its trajectory change (very slight pull up), indicating the missile lost track. At the same time the A-10 is beaming and dispensing CM like crazy, which is what defeated your missile. Good job by the A-10 pilot.

 

Similarly your R-73 stops tracking as soon as the A-10C starts dispensing again ( 14:55:38 ), although I have no clue where it's going. It wasn't a good launch angle anyways since the A-10's engines are rather cold in comparison and they were masked by the stabilizers at the back.

[Cmptohocah]

Your R-27 clearly makes a slight right turn after launch. You probably didn't see it from the cockpit, but it's easy to see with free camera in TAC.

 

At 14:55:32 you can see its trajectory change (very slight pull up), indicating the missile lost track. At the same time the A-10 is beaming and dispensing CM like crazy, which is what defeated your missile. Good job by the A-10 pilot.

 

...

 

Thanks for replying fudabidu.

From what I can see in TacView the first R-27R @ 14:55:37 seems to be intercepting initially, but as the flight path develops it's evident that it's flying in a straight and very shallow climb. Radar lock was never broken, chaff are being dispensed from the rear of the A-10, so I am wondering what stopped it from either tracking the target or the chaff as it usually does?

Beaming defeats the doppler radar, 'cause the radar can't differentiate the a/c from the ground. The lock was kept throughout, so what turned the missile seeker blind?

 

The last R-73 is running away from the A10 as it got scared :D

Would understand that it went for flares, or tracked and lost the A-10, but instead it went in completely opposite side and in a very sharp turn too.

 

But what confuses me the most is the R-27R. I just don't understand what effect would it cause to do this?

 

 

 

[dundun92]

Looking at the tacview it was 100% notched + chaffed. The lock wasnt broken long enough for you to notice probably, but his turning through the notch + chaff was what defeated it.

[Cmptohocah]

Looking at the tacview it was 100% notched + chaffed. The lock wasnt broken long enough for you to notice probably, but his turning through the notch + chaff was what defeated it.

 

Hi dundun92,

the lock was not broken at all, and why would it be? The radar was not in look-down situation.

[BlackPixxel]

After the R-27 is fired, the A-10 turns through the notch, which will make the lock transition to EO only.

 

And because the Su-27 systems are not properly modelled (for balancing in the old Flaming Cliffs days propably) the radar will not keep painting the target with guidance illumination by being slaved to the angular coordinates of the IRST, as it would do IRL.

 

So there is no radar illumination and the missile is not guiding.

 

Make sure that when the target exits the notch, to press the EO button once. This will cause the lock to switch back into a radar lock, which would cause SARH missiles to guide again. Sometimes the radar does not turn on automatically.

 

But in most cases the missile is already trashed when the lock transitions to EO, because of this old bug: https://forums.eagle.ru/forum/english/digital-combat-simulator/dcs-world-2-5/bugs-and-problems-ai/weapon-issues/255225-reported-r-27er-goes-for-chaff-when-lock-is-lost?t=253434

It basically causes the missile to suddenly turn into chaff as soon as the radar stops emitting, which is of course extremely unrealistic.

[Cmptohocah]

After the R-27 is fired, the A-10 turns through the notch, which will make the lock transition to EO only.

 

And because the Su-27 systems are not properly modelled (for balancing in the old Flaming Cliffs days propably) the radar will not keep painting the target with guidance illumination by being slaved to the angular coordinates of the IRST, as it would do IRL.

 

So there is no radar illumination and the missile is not guiding.

 

Make sure that when the target exits the notch, to press the EO button once. This will cause the lock to switch back into a radar lock, which would cause SARH missiles to guide again. Sometimes the radar does not turn on automatically.

 

But in most cases the missile is already trashed when the lock transitions to EO, because of this old bug: https://forums.eagle.ru/forum/english/digital-combat-simulator/dcs-world-2-5/bugs-and-problems-ai/weapon-issues/255225-reported-r-27er-goes-for-chaff-when-lock-is-lost?t=253434

It basically causes the missile to suddenly turn into chaff as soon as the radar stops emitting, which is of course extremely unrealistic.

 

That's an interesting point. I do have some things that are not clear to me though.

First thing is: Does radar suffer from notching in a look up position? If yes, why? I understand why it works in a look-down, as the radar can't separate the target from the ground returns, ie. there is no shift in frequency.

Second: If my EOS was able to track the A-10, why was the 2nd R-73 flying away from the A-10? Does EOS have better tracking capabilities than the R-73?

 

Thanks for your answers guys!

[draconus]

Notching is beaming in a look down. That will break the lock.

Beaming itself does not do much unless you have 0 speed (like ground radar). Same as if you persuit the target matching its speed. Doppler filter will break the lock.

R-73 is fire and forget - once fired your EOS does not help it.

[Cmptohocah]

Notching is beaming in a look down. That will break the lock.

Beaming itself does not do much unless you have 0 speed (like ground radar). Same as if you persuit the target matching its speed. Doppler filter will break the lock.

R-73 is fire and forget - once fired your EOS does not help it.

 

Hi draconus,

if what you wrote is true, and this is what I was thinking also, there should be no reason for the radar lock to drop as I was below the target, ie. no ground returns. We are then back to square one: why did the lock break, if it did, and if it didn't, why did the R-27R not track the target?

I understand that R-73 is fire 'n' forget, I was just referring to why didn't it track the target when EOS clearly had no issues keeping track? Not only that it didn't rack it, it seems to have flown away in completely different direction.

[Ironhand]

 

...there should be no reason for the radar lock to drop as I was below the target, ie. no ground returns...

If the gate is in effect, the gate is in effect. If set to ignore returns that drop below 20 km/hr (for example), it will do that regardless of direction. That is true unless, in a look-up situation, the gate is removed. Don't know if that occurs automatically in this radar or not.

 

[dundun92]

The shot was a lookdown shot though. You were at 1100ft, he was at 900ft. Lookup/down for SARH only matters relative to you, not the missile in DCS anyway. The missile isnt illuminating the target, and as Pixxel said the radar lost lock (even if for a split second) and likely switched to EOS during the notch, and the missile then stopped guiding. His chaff stopped it from reacquiring.

[dundun92]

I understand that R-73 is fire 'n' forget, I was just referring to why didn't it track the target when EOS clearly had no issues keeping track? Not only that it didn't rack it, it seems to have flown away in completely different direction.

EOS does not track flares in DCS, whereas missile seekers can. And yes the EOS has better tracking than the R-73 seeker.

[Cmptohocah]

The shot was a lookdown shot though. You were at 1100ft, he was at 900ft. Lookup/down for SARH only matters relative to you, not the missile in DCS anyway. The missile isnt illuminating the target, and as Pixxel said the radar lost lock (even if for a split second) and likely switched to EOS during the notch, and the missile then stopped guiding. His chaff stopped it from reacquiring.

 

Yes, you are right. I had another look from the cockpit and it seems that the target really was engaged in a look-down situation.

 

Does this imply that the radar can loose a lock in this way, regardless of the target distance, ie. power of the radar signal? This is the area, I don't really have great expertise in.

 

[dundun92]

Notching works at any range yes. Now, at longer ranges, the target will break lock while beaming simply because it is outside the detection range for beaming targets. But this is much inside that range.

[draconus]

Afaik the closer to the ground the target is the harder it is for the radar to differentiate notching target from the clutter, but DCS does not go that deep in simulation.

[Ironhand]

...

 

Does this imply that the radar can loose a lock in this way, regardless of the target distance, ie. power of the radar signal? This is the area, I don't really have great expertise in.

 

...

This is what the manual has to say:

 

”The aspect angle of the target detectable by the RLPK is limited by the radial component of its velocity. At subsonic speeds, the aspect angle should not exceed 70° regardless of the hemisphere and circumstances of the attack.

 

When attacking a target, if maneuvering will alter the angles in a way that can change the target’s hemisphere, set the PRF: FRONT (Hemisphere)-AUTO-REAR (Hemisphere) (ППС-АВТ-ЗПС) switch to the AUTO position.

 

 

In Continuous Bearing mode (STT), the RLPK ensures all aspect tracking of a maneuvering target against uncluttered backgrounds. Target maneuvers can include course reversals and turns with a target elevation (угле места цели) of more than 3° (at a range of under 30 km).

 

When attacking a maneuvering target which produces an aspect angle (ракурсу на углах) of less than 3° with the target in ground clutter, in either Front Hemisphere PRF or Rear Hemisphere PRF, tracking is ensured as long as your closure rate (either positive or negative) is 150 km/h or more. At subsonic speeds this corresponds to an angle of approximately 80°.

 

For either larger aspect angles or azimuths greater than 60°, the target will be dropped.”

[GGTharos]

Hi draconus,

if what you wrote is true, and this is what I was thinking also, there should be no reason for the radar lock to drop as I was below the target, ie. no ground returns. We are then back to square one: why did the lock break, if it did, and if it didn't, why did the R-27R not track the target?

I understand that R-73 is fire 'n' forget, I was just referring to why didn't it track the target when EOS clearly had no issues keeping track? Not only that it didn't rack it, it seems to have flown away in completely different direction.

 

Regardless of IRL nuances, here's what matters in DCS for the FC3 birds and anything using their radar code, as well as missiles:

 

Look-down means 'below own altitude', period.

The notch filter is engaged in look-down for ownship radar and the missile's radar (That seeker is a radar).

The notch filter is larger the further away a radar is in DCS. Inside some 10nm (or 10km, I forget) the notch filter shrinks significantly but it's not zero.

A momentary pass through the notch can trash a missile, probably a bit easier in DCS than IRL.

Chaff is least effective head-on, most effective on the beam, and very effective behind the 3-9 line.

Look-down makes chaff more effective.

More chaff bundles make chaff more effective.

 

Missiles also have chaff rejection scores, so take the above chaff effectiveness and combine it with that.

 

So, for a radar guided missile's guidance, head on look-up high-speed target is the best case, beam-on look-down slow-ish target is the worst case (with tail-on coming a fairly close second).

 

Regarding heaters doing weird things - yep, put enough flares in its FoV and the thing will go nuts. Also happens IRL.

 

For heaters, head-on is the worst case (IR signature is mostly masked, making flares more effective and also detection range drops)

Look-down makes flares more effective.

More flares in the FoV make flares more effective.

Sun being within some 20deg of your shot can be bad news for the heat seeker.

[draconus]

 

Regardless of IRL nuances, here's what matters in DCS for the FC3 birds and anything using their radar code, as well as missiles:

...

 

Regarding DCS model:

Are the engines off/power setting/AB taken into consideration for heaters?

Can some (doppler?) ground radars be defeated by beaming alone?

Since the beaming aspect increase the RCS (base value * aspect variable) but at the same time makes it a harder target for radar detection - which one of the effects is stronger?

Do you have any info on better radar codes on FF modules? (I only heard of AG modes (doh!) and HB's additional radar simulations)

[GGTharos]

 

Regarding DCS model:

Are the engines off/power setting/AB taken into consideration for heaters?

 

Yes, it's AB/no-AB, and I think 'off' may have an effect as well. But there's nothing 'inbetween', just those three discrete positions.

 

Can some (doppler?) ground radars be defeated by beaming alone?

 

Yes.

 

Since the beaming aspect increase the RCS (base value * aspect variable) but at the same time makes it a harder target for radar detection - which one of the effects is stronger?

 

The RCS does not change with aspect changes in-game.

 

Do you have any info on better radar codes on FF modules? (I only heard of AG modes (doh!) and HB's additional radar simulations)

 

No, I do not but for the most part they seem to work the same way with respect to these things.

[draconus]

Something is changing with aspect as you can observe different detection ranges for the same target. Closure rate?

[dundun92]

Something is changing with aspect as you can observe different detection ranges for the same target. Closure rate?

 

Yes, low aspect (or simply slow) targets have lower detection ranges simply due to the lower closure, this is most emphasized in HPRF.

[GGTharos]

Something is changing with aspect as you can observe different detection ranges for the same target. Closure rate?

 

There may be a basic RCS 'template' based on aspect but it would require a bunch of tests to figure that one out. If it's there, great.