R-27T/ET Lock-on After Launch? - ED Forums
 


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Old 05-10-2020, 04:52 PM   #1
Cheetah7798
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Default R-27T/ET Lock-on After Launch?

After reading the (en) wikipedia article on the R-27 series of missiles, my interest was piqued by a rather poorly written paragraph about the R-27T/ET under the 'variants' header which appears to suggest LOAL capability for the missile's T/ET variants.

It references the manual for the Su-27SK export model, and sure enough, after cross-referencing what little I could, various essential pieces of information seemed to correspond. Specifically, the terms 'ППС', 'Р-27ЭТ1(Р-27Т1)' and finally '15 degrees'. That's about all I could translate if you want to call it that.


Here are two snippets from Wikipedia and the manual. Hopefully not stepping on any server rules with this one:

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Wikipedia:
https://en.wikipedia.org/wiki/R-27_(air-to-air_missile)
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Manual:
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Firstly, I can't read Russian beyond recognizing the characters, so it would be nice to know if the manual does indeed align with the Wikipedia article.

Secondly, am I correct in understanding that this suggests, with a hard-lock, in PPS mode, with no seeker lock or 'LA', you may fire a T/ET missile in the target's general direction (+- 15 degrees) and expect a LOAL?

Finally, does any of this work in DCS? As far as I'm aware, it doesn't.

EDIT:
- Fixed link

Last edited by Cheetah7798; 05-10-2020 at 05:03 PM.
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Old 05-10-2020, 05:34 PM   #2
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You can use yandex with OCR to easily translate scanned/photographed documents:
https://translate.yandex.com/ocr

These 15° in the manual are something different than described in the Wikipedia article:
You don't want the target aircraft pointed directly towards you, but at least 15° away from you (can be up/down/left/right) for a better missile lock.

Propably because then because the aircraft exhaust is not covered by the fuselage that much.
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Old 05-10-2020, 07:46 PM   #3
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As far as DCS goes, you can lock your target with radar and then fire R27T/ET using launch override even without launch authorization. I don't really know what goes on under the hood, but it seems that the missile will fly some kind of datalink intercept course and when close to the target acquire by itself and hit. It looks like the intercept course is only calculated on launch and not updated during flight though (?)
It needs more investigation...
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Old 05-11-2020, 02:06 PM   #4
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Yep, scored some 50km hits like that, high and fast launch, turn cold. Dude flies into it.
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Old 05-12-2020, 02:10 AM   #5
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You can do LOAL launches with the R-27T/ET but you have to be very, very careful because the missile receives no mid-course guidance and will lock on to anything it detects - no IFF involved.

Can be useful for really long range head-on shots (f-pole) or an extending range tail chase shot but again you have to be really careful with possible target deconfliction. Ask me how I know
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Old 05-12-2020, 06:42 PM   #6
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Quote:
Originally Posted by baronnomis View Post
As far as DCS goes, you can lock your target with radar and then fire R27T/ET using launch override even without launch authorization. I don't really know what goes on under the hood, but it seems that the missile will fly some kind of datalink intercept course and when close to the target acquire by itself and hit. It looks like the intercept course is only calculated on launch and not updated during flight though (?)
It needs more investigation...
If it does any turn to target without the seeker being locked on, that's wrong.

The launch override for these missiles is meant to jettison the missiles, not launch them at targets. Your seeker might not even be cooled, and you can't guarantee what it'll lock on to - you're just lucky in DCS that other than aircraft, it can only lock onto the sun (And flares) but no cloud/water/other reflections or heat sources.

There is ZERO LOAL capability for these missiles IRL. They are meant to be launched with lock on the rail and AFAIK the WCS provides zero guidance to the missile other than to slave the seeker to EOS/Radar.
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Old 05-13-2020, 08:19 AM   #7
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After testing, it seems that R-27T/ET missiles will get course updates just like the R/ERs. Launches of T/ET missiles without a seeker lock, in weapon launch override mode will guide them out to the target until the seeker becomes active.

This is inconsistent with what is stated on the Wikipedia page (And, I assume, the Su-27SK manual).

This begs the question, does the T/ET have a datalink with the firing aircraft?

According to this article by Air Power Australia, it appears to suggest that the Datalink is purely associated with the R/ER variants.
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https://www.ausairpower.net/APA-Rus-BVR-AAM.html

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Old 05-13-2020, 10:10 AM   #8
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There is zero mid course update for R-27T/ET in DCS.

All it knows is the target position during the launch, and it turns roughly towards that position using INS. From that point it is flying straight. If the target happens to be within the narrow seeker FOV at some point within the necessary range for a lock, then the missile will start tracking.
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Old 05-13-2020, 11:41 AM   #9
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Quote:
Originally Posted by BlackPixxel View Post
All it knows is the target position during the launch, and it turns roughly towards that position using INS. From that point it is flying straight. If the target happens to be within the narrow seeker FOV at some point within the necessary range for a lock, then the missile will start tracking.
AFAIK, it doesn't have an INS, as it has an IR seeker with no LOAL capability. If the seeker has no lock before launch, it has no knowledge of any targets and it can't be launched, except in a case of emergency because it can't be jettisoned like e.g. the radar variants on the AKU pylons.
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Old 05-15-2020, 04:39 PM   #10
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Quote:
Originally Posted by GGTharos View Post
If it does any turn to target without the seeker being locked on, that's wrong.

The launch override for these missiles is meant to jettison the missiles, not launch them at targets. Your seeker might not even be cooled, and you can't guarantee what it'll lock on to - you're just lucky in DCS that other than aircraft, it can only lock onto the sun (And flares) but no cloud/water/other reflections or heat sources.

There is ZERO LOAL capability for these missiles IRL. They are meant to be launched with lock on the rail and AFAIK the WCS provides zero guidance to the missile other than to slave the seeker to EOS/Radar.
I am of course talking about DCS only. I have absolutely no data on how it works IRL.
But are you sure the LA override is there to jettison the missile? I was under the impression, that it is there for you to be able to launch the missile if you are not in range (for whatever tactical reason).
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