IRST ranges

[AeriaGloria]

Hello, I did some IRST testing. And Welp, it’s true the IRST is not very good 

F-15/F-14

Head on-12 km, 24 km AB

Side: 16 km, 36 km AB

Rear: 20 km, AB, 42 km AB

F-4 slightly higher in Mil

 

F-18 

 

Head on: 10 km. 22 km AB

Side: 14 km, 30 km AB

Rear: 19 km, 40 km AB

 

F-16

Head on: 10 km, 18 km AB

Side: 13 km, 29 km AB

Rear: 17 km, 35 km AB
 

Edited Wednesday at 10:32 AM by AeriaGloria

[Pavlin_33]

I think IRL radar jamming might be an issue, that's where EOS/27T come in.

[Dragon1-1]

Plus, your target doesn't get RWR nails, which is nice. The MiG-29 IRST is basically the R-60 seeker head with a few tweaks, so range isn't that impressive, but it's still useful.

[CrazyGman]

9 hours ago, AeriaGloria said:

Hello, I did some IRST testing. And Welp, it’s true the IRST is not very good 

F-15/F-14

Head on-12 km, 24 km AB

Side: 16 km, 36 km AB

Rear: 20 km, AB, 42 km AB

F-4 slightly higher in Mil

 

F-18 

 

Head on: 10 km. 22 km AB

Side: 14 km, 30 km AB

Rear: 19 km, 40 km AB

 

F-16

Head on: 10 km, 18 km AB

Side: 13 km, 29 km AB

Rear: 17 km, 35 km AB
 

I mean I find the IRST modes useful for the obvious close range engagments. And for locking beaming and cold targets, and the slaving of the radar to support which is kinda it's intended role anyway which was to assist aquiring rear aspect targets. The search mode I do find I use the least, execpt to switch to once I IRST lock in either helm or IRST CC so I can then lock beaming or cold targets with the radar again outside 10km.

It's main limit is trying to reaquire targets that have gone head on again but not in AB. Inside 25km but outside 10km So you have to either switch to the radar and try to aquire that way, or get IRST lock at 12-10km, at which point your at best firing second against your opponent.

Edited Wednesday at 07:23 PM by CrazyGman

[CrazyGman]

On another note. I really like how on the exterior model when you cycle through the IRST modes you can see the seeker move. In IRST search you will see it move side to side and up and down as it scans, and in IRST cc it fixes forward and moves up and down at a faster pace. It's subtle, but if you look closely you'll see it.

Edited Wednesday at 07:31 PM by CrazyGman

[TotenDead]

4 часа назад, Dragon1-1 сказал:

Plus, your target doesn't get RWR nails, which is nice. The MiG-29 IRST is basically the R-60 seeker head with a few tweaks, so range isn't that impressive, but it's still useful.

 R-60 seeker you say... 

[AeriaGloria]

The KOLS head itself is about the size of the R-27T/ET seeker head, but behind that opaque cover I would bet the actual mirror of the R-27T/ET is smaller and collects less light. 
 

However, like R-73, I would bet the cross seeker of the R-27T/ET is InSb sensor material. While KOLS 14 element seeker is using worse PbSe (same sensor material as R-60M, but of course much larger material and more sensor elements using a cross type seeker arrangement). Brochures for R-27T/ET give a 15 km head on range and 70 km rear aspect range against an “average target,” which I would assume to be tested against Su-15 (as for Su-27 material when they reference F-15 type IR target the actual test was done against Su-15). 
 

I might test, but I would bet R-27T/ET is superior on all situations. 
 

R-73 on other hand has charts that were also tested against Su-15 and show much shorter ranges then we see with KOLS in DCS. I would bet its seeker is also InSb, and it also uses a cross type seeker. But by virtue of being smaller must just not be able to compete with the much larger 14 element PbSe seeker of the MiG-29 (14 element in search, 6 in tracking though). 
 

Thing is PbSe and InSb also see different wavelengths, it is assumed that InSb is much better at seeing a heated up airframe and thus better front aspect, while PbSe mostly looks for engine plume, and thus is much worse at front aspect and primarily good for side and rear aspect. 
 

In this brochure. 36T is original R-27T/ET seeker. While it gives 15 km for front aspect, similar brochures gives 10-12 km for R-73, which if we compare to a chart for its seeker, is quite very optimistic 

I know someone online who was able to scan German documents in an archive that also has a 360 degree graph of R-60 seeker acquisition, which gives a very good idea of the head on/side/rear aspect abilities of PbSe. 
 

In that graph, R-60 does about 1.3 km head on, 1.6 km side on, and 4.4 km rear aspect. For AB its front 2.4 km, side 3.2 km, and rear beyond ballistic range. So you can see this is far below KOLS

4 hours ago, CrazyGman said:

On another note. I really like how on the exterior model when you cycle through the IRST modes you can see the seeker move. In IRST search you will see it move side to side and up and down as it scans, and in IRST cc it fixes forward and moves up and down at a faster pace. It's subtle, but if you look closely you'll see it.

Fun fact, IRST sensor is exactly like radar in that it only needs to move 50% of the angle needed. So to look 30 degrees in one direction, both sensors only tilt the mirror/antenna 15 degrees since both are “cassegrain” type sensors. 

Edited Wednesday at 11:33 PM by AeriaGloria

[MA_VMF]

8 часов назад, AeriaGloria сказал:

The KOLS head itself is about the size of the R-27T/ET seeker head, but behind that opaque cover I would bet the actual mirror of the R-27T/ET is smaller and collects less light. 

ГСН Р-27Т/ЭТ охлаждаемая в этом и разница между ей и КОЛС

[AeriaGloria]

2 hours ago, MA_VMF said:

ГСН Р-27Т/ЭТ охлаждаемая в этом и разница между ей и КОЛС

Well to be more specific, the KOLS head is cooled, Peltier cooled. However PbSe has a limit to how much it can be cooled, and if it’s like the R-60M seeker which is also a Peltier cooled PbSe seeker, it is likely cooled only to 40° C below ambient.
 

However the R-27T/ET 36T seeker is cooled by nitrogen to -360° Celsius, so both are cooled. But 36T cooled to a much higher degree from the nitrogen and InSb working so well at such low temperatures. 

Edited yesterday at 07:53 AM by AeriaGloria

[Vakarian]

1 minute ago, AeriaGloria said:

However the R-27T/ET 36T seeker is cooled by nitrogen to -360° Celsius, so both are cooled. But 36T cooled to a much higher degree from the nitrogen and InSb working so well at such low temperatures. 

Very highly doubt that

[AeriaGloria]

3 minutes ago, Vakarian said:

Very highly doubt that

I am just repeating what is said in MiG-29 manuals. Perhaps it meant 360 degrees below ambient. 

[Vakarian]

20 minutes ago, AeriaGloria said:

I am just repeating what is said in MiG-29 manuals. Perhaps it meant 360 degrees below ambient. 

Even so, absolute zero is 0 Kelvin or -273.15 Celsius. For seeker to be cooled 360 degrees below ambient (I assume Celsius as I assume Russians use that as the unit of measurement) that would mean the ambient temperature is at the minimum 86.85 Celsius, which would assume chilling the sensor to absolute zero which takes an immense amount of energy to accomplish.

[AeriaGloria]

57 minutes ago, Vakarian said:

Even so, absolute zero is 0 Kelvin or -273.15 Celsius. For seeker to be cooled 360 degrees below ambient (I assume Celsius as I assume Russians use that as the unit of measurement) that would mean the ambient temperature is at the minimum 86.85 Celsius, which would assume chilling the sensor to absolute zero which takes an immense amount of energy to accomplish.

I wonder what they meant then 

“The thermal homing head has two photodetectors: one is deeply cooled to a temperature of -360°C, and the other is uncooled.”

[MA_VMF]

4 часа назад, AeriaGloria сказал:

However the R-27T/ET 36T seeker is cooled by nitrogen to -360° Celsius, so both are cooled. But 36T cooled to a much higher degree from the nitrogen and InSb working so well at such low temperatures. 

77K, absolute zero -273,15. 

[Dragon1-1]

The only way that number works is if it's in Fahrenheit. Nitrogen evaporates at -196°C or -321°F, so an LN2 cooled seeker can only ever be at that temperature, no matter what the manual says. If we assume a cool 39°F day on the test range in Russia, the seeker will indeed be cooled to -360°F below ambient. 

Either that, or it's a misprint. In contest of nitrogen cooled anything, it's a nonsensical number.

[AeriaGloria]

It makes me wonder how OLS-27 works, as Su-27 gets much more range from its IRST with reportedly 15 km head on and 50 km rear detection for F-15 type target (Su-15). I wonder if perhaps it uses nitrogen or still peltier cooling, and I’m sure it uses InSb instead of PbSe 

[AeriaGloria]

Reading a KOLS manual for a future video I’m planning, it says “

Ensures reduction

photodiode temperature to 70-80°C. .” 
 

I don’t know if it means -70-80° total or just below ambient 

[MA_VMF]

16 часов назад, Dragon1-1 сказал:

The only way that number works is if it's in Fahrenheit. Nitrogen evaporates at -196°C or -321°F, so an LN2 cooled seeker can only ever be at that temperature, no matter what the manual says. If we assume a cool 39°F day on the test range in Russia, the seeker will indeed be cooled to -360°F below ambient. 

Either that, or it's a misprint. In contest of nitrogen cooled anything, it's a nonsensical number.

-196С=77K