Su-25T DIRCM suddenly became almost 0 effective. Why?

[Maverick Su-35S]

Hi,

          Playing DCS since KA-50 (almost 2 decades ago) I have witnessed the foreseen and the unforeseen. Now, I know that the DIRCM is basically a system designed to spot the plume of missiles within a given FOV and interpret them as real missiles or not within some given false positive error. It's purpose was to detect IR missiles although I doubt that it's able to differentiate between radar or IR missile in reality simply because it looks for a plume pattern left behind by any missile. So it basically warns you about it. After detecting that a missile is incoming, a rapidly rotating laser with a given divergence and beam intensity will eventually pass over the IR missile's seeker head, rapidly and repeatedly heating it up, up to the point of making it become completely unable to distinguish any heat signature anymore, because IR missile's seekers are highly cooled to be able to track heat targets better. The cooler the seeker, the better the lock, the hotter the seeker, the weaker the lock. That's why IR missiles are so limited in range..., not because they can't reach far. Just look at how now the IRIS-T is modeled in DCS. AT LAST..., after arguing so many times with so much logic and personal proof years behind, everyone was laughing at me until they found out that I was right, that missiles should have much more reduced drag than they had and so now we can see the IRIS-T, with better CD vs AOA tables implemented, that it has greater flight range than an AIM-120C once had (years ago). BRAVO! You guys finally found out what I was saying back then about the too high AA missiles drag at low AoA and too low drag at high AoA...! So, back to the subject, the faster a missile will fly through the air, at a greater rate it's seeker will heat up, because these are the laws of physics. So, even if an IR SAM missile can travel even past 10km down range, say... a MIM-72 Chapparal missile or IRIS-T, it's seeker will heat up in less than 4km high enough to lose the track on the locked heat source.

The DIRCM does just that, it heats the incoming missile's seeker at a fast rate. Basically, if a missile is close enough to a DIRCM equipped aircraft, let's say less than 1km away, the DIRCM will first lose some time to react and start pointing the laser in repeated motions over the missile's seeker and missile will be close enough to not loose the lock on the heat source before it's seeker is hot enough. At least, that's how I find it pretty simple and logic to see. From too close, no DIRCM will be able to stop any IR missiles due to those key details. From further away, a function of time will greatly reduce an IR missile's PK without the use of any flares..., just simply because the chance of losing lock from random factors will occur.

With basically a function of atmospheric temperature, missile speed and time of DIRCM actively heating a missile's seeker, there is a range between the launch site and the target after which that missile will lose lock 100% of times. Basically the PK becomes ZERO for good!

I don't know what happened after X latest update, but one year ago I could have more than 90% of the missiles that were coming from the aft hemisphere of my Su-25T go by my plane without hits and today almost 0% of those missiles do that anymore. Now, with or without DIRCM, from far or from close, when an IR missile is coming for the Su-25T, it hits it like the DIRCM doesn't exist. Ah..., and by the way, in the past the DIRCM was only affecting IR SAM missiles, AA IR missiles were 0% affected by the DIRCM anyway. Now even the IR SAM missiles are not affected by the DIRCM? What is the new logic now?

Thanks!

[Maverick Su-35S]

I was wrong about the DIRCM not working at all. It does indeed not work at all on IRIS-T and AA missiles for no reason, but maybe this will hopefully be corrected in the future, cause all IR missiles are badly affected by a heating laser on their seeker. The DIRCM's field of work has been drastically reduced though (after some X update) from some 90 degrees (45 left/right/up/down) to just some 20 degrees (10 left/right/up/down) from the back of the plane and that's why I initially had the impression that it's not working anymore. It does, but it's almost useless as it only works on SAM IR missiles (except the faulty IRIS-T and AA missiles) if the incoming missile is within some maximum 10 degrees offset of the Su-25Ts centerline when closing in from behind. Here are the tracks:

Thank you!

AA missiles are unaffected by DIRCM.trk DIRCM limited to only 20deg from around 100deg.trk IRIS-T also unaffected by DIRCM.trk

[Skuva]

Isn't the IRCM on the 25T just like a stroboscopic infrared light that interfere signal gain of spinning seeker reticles? So imaging seekers like IRIS-T / AIM-9X just track you normally.

Similarly for DIRCM systems, it can't fool imaging seekers, because these systems are not blinding the seeker, but giving it false information through its signal modulation.

 

EDIT: I found this interesting article, which details the effects of lasers over one type of imaging seeker, if anyone is interested. https://publications.tno.nl/publication/34611937/NAmFxx/schleijpen-2007-imaging.pdf

It shows that lasers can produce ghost images on the sensor. But I assume given the ghost image is always close to the targets it wouldn't be enough by itself to make the missile miss. But maybe the laser is capable of helping changing the shape of the target so when used in conjunction with flares, could fool more advanced shaped recognition imaging seekers.

Edited October 20 by Skuva

[Maverick Su-35S]

On 10/20/2025 at 12:36 AM, Skuva said:

Isn't the IRCM on the 25T just like a stroboscopic infrared light that interfere signal gain of spinning seeker reticles? So imaging seekers like IRIS-T / AIM-9X just track you normally.

Similarly for DIRCM systems, it can't fool imaging seekers, because these systems are not blinding the seeker, but giving it false information through its signal modulation.

 

EDIT: I found this interesting article, which details the effects of lasers over one type of imaging seeker, if anyone is interested. https://publications.tno.nl/publication/34611937/NAmFxx/schleijpen-2007-imaging.pdf

It shows that lasers can produce ghost images on the sensor. But I assume given the ghost image is always close to the targets it wouldn't be enough by itself to make the missile miss. But maybe the laser is capable of helping changing the shape of the target so when used in conjunction with flares, could fool more advanced shaped recognition imaging seekers.

Wow..., just stumbled upon a person who has some knowledge. Nice to respectfully salute you then!

"Isn't the IRCM on the 25T just like a stroboscopic infrared light that interfere signal gain of spinning seeker reticles? So imaging seekers like IRIS-T / AIM-9X just track you normally."

Just learned it from you know. I only knew somewhat about the DIRCM. But still, so it means that the DIRCM should still have an impact in tracking performances of missiles like IRIS-T and AIM-9X, by giving false information into the seek head, as you've said.

I AM INTERESTED. As an ex-aerodynamicist and aerospace engineer with more than a decade of experience in flight dynamics and aerodynamics, I'm interested of everything I may learn for myself and others (when helpful) about any other subject, not only aerodynamics. Many thanks for the effort to put that link.

Edited Thursday at 02:05 PM by Maverick Su-35S
Added some context.

[Maverick Su-35S]

Just from reading now from that article, this aspect may have been overlooked by most of us: the outside temperature=)). Heh..., indeed it matters a lot in affecting an IR seeker but we usually focus on other complex details and forget this:

From that article's text:

Environmental
Thermal range 0° to 30°C
Relative humidity 0% – 50% RH

And also:

" The upper level was selected to avoid and damage to the detector." This can tell (at least I'd do that if I were to design a military DIRCM, to save an aircraft with) that the military DIRCM uses higher intensity laser to make sure that it does all the havoc to the incoming missile's seeker, burn it out if possible, not just affect it's precision.

I don't know, now I may ask the dumbest question: Does that mean that over 30C of outside temp, the seeker looses it's tracking capability? Besides this question about what does that temp limit want to say,, I understand that the article was based on a simulator that they've created for research and it does not represent the real performances of a military IR missile seeker, but still, it's a research and how far from the military thing can it go? Just common sense!

Edited Thursday at 02:49 PM by Maverick Su-35S
Added more context

[Maverick Su-35S]

On 10/20/2025 at 12:36 AM, Skuva said:

It shows that lasers can produce ghost images on the sensor. But I assume given the ghost image is always close to the targets it wouldn't be enough by itself to make the missile miss...

Agree, but by what margin would the missile's interception error build up? Even 2 meters away from the ideal detonation distance from the target could make minimal to no damage on the target, especially if the target is faster and the missile detonates behind. There was that funny interesting fact with that Saudi F-15 which was flying straight, was warned that a missile is coming (dunno how the pilot knew), the pilot did the dumbest things possible..., put full AB, dropped just 2 pair of flares, continued to fly straight, didn't even budge to pull up or do a turn or anything, and the blinded R-27T SAM blew up somewhere to the left and above that F-15, so..., just many meters away and did little damage on it's frame and skin and elevators if I recall correctly. So, that pilot escaped ejection or death even though he did what was dumbest of all, putting AB in full blast and still escaped by luck as the missile blew up and to the left, enough meters away to cause anything critical.

So..., drawing from that example, if a DIRCM is able to make the imaging seeker have errors in it's final trajectory and intercetion, EXACTLY AS IT ACTUALLY IS SIMULATED NOW IN DCS on the SU-25T, but unfortunately only on the non-imaging seekers which should otherwise be losing track on the DIRCM emitting target maybe at least half a mile before reaching their target, the way these non imaging seekers missiles behave in DCS should be the way the IRIS-T and AIM-9X imaging seeker heads should be affected, just like that, by starting to lose interception precision and most logically detonate meters away from the unaffected initial detonation distance or simply just fly by if their detonation system only activates the detonation if the target is below X meters away and if not, the missile goes flying by.

What do you think?

Edited Thursday at 02:46 PM by Maverick Su-35S
added the video as a reminder of possibilities

[Maverick Su-35S]

I consider this topic should be moved to the scientific or research part of the ED forums! I've always wished the best for DCS through ED, although I've gotten tired over the years of being mocked by those with little intelligence and knowledge, ignored, whatever, so I'm used to it now!