PL-5EII seeker performance in uncaged mode

[Lynnux]

DCS open beta 2.8.x

Winter night, -10°C (cold environment)
Altitude: 15000 feet
Target: MiG-15

Target is passing co-alt in front of me, left to right. It's locked on radar the whole time. The PL-5E is slaved to radar (=rotating seeker symbol over target).
The right aspect to rear-right aspect distance was 2 nm to 1 nm, the PL-5E didn't lock.
After the target passed I followed it. The PL-5E locked at rear aspect, distance 0.4 nm.

Merging head-on with the target the PL-5E doesn't lock or only at a very short distance (too close).

So the seeker performance currently is clearly rear-aspect, like AIM-9B. Is this realistic / ok ?

The MiG-15 seems to be a quite stealthy plane, especially concerning the IR signature. But with e.g. the Matra Magic II I didn't observe this poor seeker performance.

Edited January 8, 2023 by Lynnux
changed title

[Tiger-II]

Regardless if "all aspect", it will always perform better from behind.

IIRC front-aspect lock ranges are 3-5 NM or so, even for AIM-9X seeker. Unless the aircraft is in max AB, the front aspect is quite cold.

I don't think it is modelled in DCS, but if you "cool the nozzle" when going for a head-on merge, you can deny a head-on heater shot completely.

I'd expect the side-aspect to be better though. At 2 NM I'd expect it to lock, but *not* necessarily track! The angluar rate of change might be too high and the target might end up out of the seeker cone before the missile can turn towards the target from such a launch geometry. Even the AIM-9X would struggle with this set-up; it would certainly lose a lot of energy in the turn.

I'd even suggest you probably ended up inside RMin for the missile.

Edited January 7, 2023 by Tiger-II

[Lynnux]

Aspect is modeled in DCS and you can even mask your AB if you point your plane directly at the enemy. And beware that the MiG-15 doesn't have AB but some patches before the PL-5EII locked at around 1.6 nm pure frontal aspect on that plane like the 1st generation "all-aspect" IR missiles (AIM-9L/M, Matra Magic II).

So my question is basically: Has the PL-5EII seeker performance been changed to rear-aspect like AIM-9B or is this a bug ?

Edited January 7, 2023 by Lynnux

[Tiger-II]

23 minutes ago, Lynnux said:

Aspect is modeled in DCS and you can even mask your AB if you point your plane directly at the enemy. And beware that the MiG-15 doesn't have AB but some patches before the PL-5EII locked at around 1.6 nm pure frontal aspect on that plane like the 1st generation "all-aspect" IR missiles (AIM-9L/M, Matra Magic II).

So my question is basically: Has the PL-5EII seeker performance been changed to rear-aspect like AIM-9B or is this a bug ?

 

What I was discussing was "cooling the nozzle", not aspect. I know it considers aspect for IR missiles. AFAIK DCS treats AB and not-AB differently, but does not distinguish between MIL and IDLE for nozzle temperature, and thus detection range. An aircraft screaming towards you at 600 kts at idle will be much harder to lock than one sat at MIL at the same speed, because the IR plume is much smaller, and the nozzle cooler due to low power and large airflow.

It sounds like a bug regardless of why. PL-5 should be all-aspect like AIM-9M, with similar seeker performance.

I suggest trying the AIM-9M and seeing what it does. If it is definitely better, then PL-5 is definitely wrong. If it is similar, then maybe something in DCS is bugged out. Try it against a different aircraft, too, in case MiG-15 is the one with the problem.

Edited January 7, 2023 by Tiger-II

[AeriaGloria]

The LUA gives the PL-5EII an all aspect cooled speaker with a seeker sensitivity that is usually twice that of most missiles from its generation, except for the AIM-9M, which has identical seeker sensitivity of 2000. There is probably other coding going on, and that coding might be intended becuase……

The PL-5EII is a 1980s-90s missile, from a time when China’s only BVR missile was licensed Sparrow/Aspides. I would have pretty low expectations of it. 
 

 

[Lynnux]

I think I found the problem. It's the "uncaged mode" when the seeker moves across a larger area and will be slaved to the target locked on radar. It can be switched on/off with the "T2_Press: AG Manual Mode/DGFT Missile Designator Control" button. In this mode the IR missile will often fail to lock. You can even follow a plane on a slightly parallel course and the missile will never lock.

Here I'm following a MiG-15 like a wingman 1.3 nm behind on a slightly parallel course. I've marked the seeker circle which constantly moves around and across the target with a small red arrow. Once I switch back to caged mode and move the seeker sufficiently close to the target, the missile will always lock.

Maybe move this thread to bugs and problems now ?

Edited January 8, 2023 by Lynnux

[Lynnux]

And here is a simple mission which will let a MiG-15 pass in front of you from left to right. It's pitch black midnight. The MiG is invulnerable and you have unlimited ammo. So you can fire as many missiles as you want but to test the seeker performance you don't have to launch one. The MiG will ignore you.

Some hints:
1. Set your throttle to a bit more than 50% before starting the mission, speeds are quite slow, stay a bit above 300 kn.
2. Switch to A2A mode when the mission has started and lock the MiG. It will be visible on the radar.
3. Assign the "T2_Press: AG Manual Mode/DGFT Missile Designator Control" to a button on your HOTAS if not done yet. So you can switch the IR seeker to "caged" and "uncaged" mode.

There is an AWACS on your side but to use the datalink you have to set it up:
COM2 channel "199", push right MFD "CLINK", switch from "Slave" to "Master" and switch Clink on, switch right MFD back to "HSD"
It's just for convenience once you've lost the target but it may be faster to just restart the mission

If you like a red target on your radar/HSD you have to switch IFF on. It's simple IFF so any mode will do (e.g. M3A).

IRmissile.miz

Edited January 8, 2023 by Lynnux

[Napillo]

7 hours ago, Lynnux said:

Once I switch back to caged mode and move the seeker sufficiently close to the target, the missile will always lock.

According to the Chinese export/import agency CATIC, the PL5E has an all-aspect capability with the seeker having a maximum off boresight angle of ±25° before launch, and ±40° after launch.

 

That said, you want it locked if you are right behind the enemy, you unlock it when you aren't sure where the enemy is, or it's a head on / beaming, either way, you listen for the tone. You don't want the seeker to lock on to a flare to the side when you are close and have a radar lock. 

[Foogle]

Try a different target aircraft, the LUA files put the Mig-15 at a 0.25 IR emission coefficient , where the SU-25 is 0.7.

Some quick non-AB numbers for you: F-16 0.6, F-5 0.4, JF-17 0.6, M2K 0.8, FW-190A8 0.1, F-18 0.75.

You've picked the least IR detectable jet aircraft possible for your test, so it's no wonder it's so difficult to lock.

Edited January 8, 2023 by Foogle
added some numbers for context

[Lynnux]

14 hours ago, Foogle said:

You've picked the least IR detectable jet aircraft possible for your test, so it's no wonder it's so difficult to lock.

That's just the "adversary plane" which is used on the MP server I'm playing on and therefore this problem was pronounced there. But there is a "huge" difference between caged and uncaged mode which definitely seems to be a bug. Especially when considering that the uncaged mode should ease locking the missile, not prevent it. I think this problem is still there with another airplane but not as pronounced/visible anymore.

But indeed I wanted to try with a MiG-21 dropping flares and maybe let an F-18 or M2K cross from right to left. It already happened to me that the missile was switching the target despite being slaved to the radar.

[Marko.H]

I have already faced this problem but didn't have enough proof to post it here. Let's move this to bugs. I've had AB-on head on flankers or eagles which the PL-5 failed to lock. I did realize that caging the seeker and manually aiming the reticle at target works around this issue and gives me a lock much much sooner.

[okopanja]

Is this still active thread?

[Napillo]

only if you make it active. Works fine for me, got an A-10 most recently with it.