R-27EA (AE) on Su-27

[Dudikoff]

but the radar needs to switch to STT, which means providing CW illumination, before the missile can be launched :)

 

Is it really a CW-illumination? I thought that R-27s have inverse monpulse seekers so that there is no need for separate CW radar mode? In that case, the targetted aircraft's RWR cannot recognize a missile launch when it occurs?

 

I might be wrong, of course, and would appreciate the explanation.

[HubMan]

Ahh ok now I understand what you mean :) .

 

No such delay exists FF.......because you can only launch an R-27R/R-27RE from STT mode ;) .

 

However, if the N001 is in SNP(TWS) mode, the system will automatically determine which of up to 10 tracked contacts will enter missile engagement range first, select it for engagement("bug" it) and only switch to STT for the launch when the system determines that target range falls within missile engagement parameters.......but the radar needs to switch to STT, which means providing CW illumination, before the missile can be launched :)

Hi Alfa, :)

 

Are you sure that CW illumination is required for the guidance of the Alamo ?

 

Because one of the -big- advantage of a 'modern' fighter monopulse radar is to be able to generate a HPRF coherent signal for tracking, that can be used by itself to guide a recent SARH missile (AIM-7M/Super 530D/Alamo ?).

 

For me, there is no need for 'illumination' as provided by a CW illuminators, excepted to give fighters with LPRF/non monopulse/crappy radar the capability to fire newer missiles or as a backup / 'historical' feature .

 

As a result, tracking a target in real life with a decent radar is enough to guide a Fox 1 (and a RWR will have a hard time trying to distinguish a lock from a shoot :) )

 

I'm know that I'm not saying anything you don't know already, I juste want to make sure I did not miss something about the behavior of the AA-10 :)

 

And by the way, I have another question : are you sure that the AA-10C cannot be fired from a TWS mode until the time the SARH seeker takes control ? Because, from a practical point of view, the only thing the missile needs during the first part of its flight is the command guidance signal provided through the secondary lobes of the radar.

 

If the missile is tuned properly before launch, it should be able to make its way without "lock" up to the point where the seeker can/must be used. Of course, if the radar do not go to STT at this point, the refresh rate of the radar on the target will probably be not high enough to provide the accuracy needed during the end game, but STT "time" sharing between two close targets (like in the Mig29 and M2000) could still be a solution with lower pk... :)

 

I've always be wondering about the "limitations" of the missiles : as exemple, I'm almost sure that most of the modern Fox 1 fitted with an INS can be guided even if the lock is lost and then regained. It should be really suprising from a tactical point of view to develop a weapon with a INS and not to use all the existing potential : firing, notching if spiked and then relocking your target, sounds far logical to me than cranking all th way and hoping that your missile will be faster than the one of the bandit :)

 

It's just a feeling, but to me, SARH missile behavior in flight sims seems far too close to the Vietnam war technology. It should be really surprising that 90's SARH systems would be that primitive :)

 

Ciao :)

 

Hub.

[golfsierra2]

Add that to a Cessna, and it's deadly too.

 

Funny, it matches with what one of my comrads said years ago about the ongoing EF2000 debate (to buy it or not): If those who wanted to save money (not buying the EF2000) had ruled, GAF still would fly Me 109, but with AMRAAM...

[Pilotasso]

They decided in favour of Typhoon because Me-109 are now worth their weight in gold. :)

[Force_Feedback]

Back to the topic, my source was a conversation between Czich and Vadigfon on the sukhoi.ru forums, they were debating wether such delay was significant (or 1 second) and how it might word. Vadifon disagreed with Czich and stated that it's not certain what is meant by 'delay' in the Weapon System squencing manual (for the Su-27, N-001 radar). Okay, this concerns the R-27(E)R, but it also applies to the EA discussion.... errrm okay, somehow...

We need realistic missiles in lomac 2, whine, cry, whine, etc....

[Alfa]

Hi Alfa, :)

 

Are you sure that CW illumination is required for the guidance of the Alamo ?

 

Hehe there are a couple of twists to that question :) .

 

In theory there should be no requirement for CW illumination for missile guidance - that is "guidance" as in the aircraft radar "controlling" the inflight R-27R missile via datalink updates to it's INS during cruise stage - because the required target coordiante accuracy(update frequency) at this stage is less than what is required at terminal stage where the missile needs to make split second course corrections to chase down the target(hence the need for a seekerhead BTW) .

 

However, if we talk specifically about R-27R/RE deployment from Su-27/MiG-29 then:

 

If in one of the search modes("Encounter", "Pursuit" or "Automatic"), making a manual target selection will send you directly to STT mode, so in this situation there isn't even any other form of radar tracking available to "collect" pre-launch target data for a missile launch.

 

If in the separate "SNP"(Track While Scan equivalent) mode, the functionality is as I described earlier:

 

"In SNP(TWS) mode, the system will automatically determine which of up to 10 tracked contacts will enter missile engagement range first, select it for engagement("bug" it) and only switch to STT for the launch when the system determines that target range falls within missile engagement parameters.......but the radar needs to switch to STT, which means providing CW illumination, before the missile can be launched".

 

So yes I am pretty confident that the N001 and N019 radars - or SUV-27 and SUV-29 firecontrol systems rather, work in such a way that you need to enter STT(Single Taget Track) radar mode in order to launch an R-27R/RE SARH missile....and I think I know why.

 

When the SARH missile enters seeker acquisition range, the SARH seeker cannot autonomously scan for the target in case the datalink'ed data is "dated" and the target isn't where the seeker is told to look for it.

 

If we were talking about an ARH missile - which we know can be launched directly from TWS - the nature of the seekerhead is such that it can autonomously scan for the target once within acquisition range - i.e. it might not require the same level of accuracy in terms of guiding the missile to seeker "wake-up" point.

 

Well it is a theory :) . Alternative explanations could be that SNP mode wasn't considered realiable enough to keep the track or simply that at the time the N019 and N001 radars were concieved, there weren't any ARH missiles around and the thought of "semi-stealthy" employment of radar missiles not really in the minds of the designers - you have a separate EOS and IR missiles for that sort of thing :) .

 

- JJ.

[4c Hajduk Veljko]

So yes I am pretty confident that the N001 and N019 radars - or SUV-27 and SUV-29 firecontrol systems rather, work in such a way that you need to enter STT(Single Taget Track) radar mode in order to launch an R-27R/RE SARH missile....and I think I know why.

 

Soviet/Russian Aircraft Weapons Since World War two” by Yefim Gordon, page 47, middle paragraph, quote:

 

“For the radar homing versions the course of action is the same but maximum lock-on range is only 40 km (25 miles). Hence it is possible to fire the R-27 (R-27ER) before target lock-on is achieved …” end of quote.

 

Then it goes on to say that the mid course correction will guide the missile until the target gets in the lock-on range. Thus the R-27 kill range is increased by some 20 km in pursuit and 60 km in head on mode.

 

This is about the missile, and you were talking about radar capabilities. Is there any airborne radar in Russian inventory that can launch R-27ER missile in the mode as described (above) in Yefim’s book?

[Dudikoff]

So yes I am pretty confident that the N001 and N019 radars - or SUV-27 and SUV-29 firecontrol systems rather, work in such a way that you need to enter STT(Single Taget Track) radar mode in order to launch an R-27R/RE SARH missile....and I think I know why.

 

I think you missed our point. The point was that CW (Continuous Wave) mode isn't used on later Russian radars because they are monopulse and the missiles have inverse monopulse seekers, meaning that they can directly guide to the echoes when the target is being continuosly "pinged" in STT mode. But this isn't the CW mode, but a pulse mode with a higher frequency, if I understand correctly. Thus, the targetted aircraft's RWR cannot distinguish when the actual launch occurs, unless it can receive the mid-course updates to the missile.

 

This a completely OT discussion which has nothing to do whether a missile can be launched without STT mode.

[Alfa]

Soviet/Russian Aircraft Weapons Since World War two” by Yefim Gordon, page 47, middle paragraph, quote:

 

“For the radar homing versions the course of action is the same but maximum lock-on range is only 40 km (25 miles). Hence it is possible to fire the R-27 (R-27ER) before target lock-on is achieved …” end of quote.

 

Then it goes on to say that the mid course correction will guide the missile until the target gets in the lock-on range. Thus the R-27 kill range is increased by some 20 km in pursuit and 60 km in head on mode.

 

This is about the missile, and you were talking about radar capabilities. Is there any airborne radar in Russian inventory that can launch R-27ER missile in the mode as described (above) in Yefim’s book?

 

Hajduk - he is simply describing the basic functionality of the R-27R/RE missile. I.e. that, unlike the IR version, the radar guided variant can be launched without a seeker lock.

 

Let's recapture:

 

Launch of IR version:

 

Target is obtained via EOS, HMS or radar - target angular position is sent directly to missile seeker, which turns to look in direction of target....if the IR seeker can lock on to it(and only then), the missile can be launched.

 

Launch of SARH version:

 

Target is obtained via radar. If the target is detected via one of the search modes, the radar needs to switch to STT to start collecting track data for a missile launch - when completed and target range falls within missile parameters the weapon can be launched.

 

If the target is detected via SNP(TWS) mode, the system will automatically determine which of up to 10 tracked contacts is the "most dangerous", select it for engagement and start generating missile launch data for it - when the system determines that the missile can physically cover the distance to target, the radar switches to STT mode and the weapon can be launched.

 

Immedeately after launch the missile heads towards target based on target coordiantes uploaded to its INS prior to launch - the aircraft radar continiously generate updated coordiantes and transmits them to the inflight missile via datalink. At terminal stage - when the target enters seeker acquisition range(what Yefim Gordon calls "lock-on range" in the quote) - the seeker looks for the aircraft radar's reflected energy and "homes"(picks up returns, processes them and determine target intercept point based on it).....i.e. the missile seeker takes over.

[Alfa]

I think you missed our point.

 

The point was that CW (Continuous Wave) mode isn't used on later Russian radars because they are monopulse and the missiles have inverse monopulse seekers, meaning that they can directly guide to the echoes when the target is being continuosly "pinged" in STT mode. But this isn't the CW mode, but a pulse mode with a higher frequency, if I understand correctly.

 

Ah yes that may well be the case - maybe I am using the term "CW" incorrectly to describe what I mean....namely that with an STT lock the radar continiously illuminates the target rather than periodically as is the case with a "TWS lock" :) .

 

Thus, the targetted aircraft's RWR cannot distinguish when the actual launch occurs, unless it can receive the mid-course updates to the missile.

 

No but while target aircraft RWR might not be able to determine the actual launch, the switch to STT(which it can detect) should be a clue that something is "cooking" :) .

 

This a completely OT discussion which has nothing to do whether a missile can be launched without STT mode.

 

Heh yeah - thats probably why I didn't quite get question there :) .

 

- JJ.

[GGTharos]

From what I've been told, that is exactly how STT is interpreted in RL - a missile launch.

 

No but while target aircraft RWR might not be able to determine the actual launch, the switch to STT(which it can detect) should be a clue that something is "cooking" :) .

[tflash]

Launch of IR version:

 

Target is obtained via EOS, HMS or radar - target angular position is sent directly to missile seeker, which turns to look in direction of target....if the IR seeker can lock on to it(and only then), the missile can be launched.

 

Launch of SARH version:

 

Target is obtained via radar. If the target is detected via one of the search modes, the radar needs to switch to STT to start collecting track data for a missile launch - when completed and target range falls within missile parameters the weapon can be launched.

 

If the target is detected via SNP(TWS) mode, the system will automatically determine which of up to 10 tracked contacts is the "most dangerous", select it for engagement and start generating missile launch data for it - when the system determines that the missile can physically cover the distance to target, the radar switches to STT mode and the weapon can be launched.

 

Immedeately after launch the missile heads towards target based on target coordiantes uploaded to its INS prior to launch - the aircraft radar continiously generate updated coordiantes and transmits them to the inflight missile via datalink. At terminal stage - when the target enters seeker acquisition range(what Yefim Gordon calls "lock-on range" in the quote) - the seeker looks for the aircraft radar's reflected energy and "homes"(picks up returns, processes them and determine target intercept point based on it).....i.e. the missile seeker takes over.

 

 

It excapes me why the R-27-ET would not use a datalink if the R-27-ER does? Is it not more logically that everything is the same except the seeker? Why waste a long-range missile with only a short-range missile seeker? In that case it would be much more logical to carry more R-73's.

 

Both the aircraft and the missile have everything that is needed to send and receive updated course info, so why not implement it and make a virtually "dud" missile out of something that could easily be the killer missile it is in Lockon.

[GGTharos]

It excapes me why the R-27-ET would not use a datalink if the R-27-ER does?

 

Because it doesn't. That's all there it to it.

 

Is it not more logically that everything is the same except the seeker? Why waste a long-range missile with only a short-range missile seeker? In that case it would be much more logical to carry more R-73's.

An R-73 doesn't have the same range as an R-27ET when chasing down a running bomber or fighter. An R-73 also has a smaller warhead ...

The R-27ET -did- have a dlink in the older version of lock on, because like you, ED made the logical assumption that hey, if one has it, so does the other. Then they got reliable info that no ... it doesn't have a data link. You can't even launch it without a seeker lock, unless it's an emergency launch in lieu of jettison (because not all pylons have the ability to jettison the missile) so you launch it off the rail instead, unguided.

 

Both the aircraft and the missile have everything that is needed to send and receive updated course info, so why not implement it and make a virtually "dud" missile out of something that could easily be the killer missile it is in Lockon.

Wrong, they do not.

It says right in the mig/flanker manual that a datalink signal is not generated for the R-27(E)T, IIRC.

The R-27(E)T is equipped with the same seeker as the R-73, IIRC, and that seeker takes over guidance immidiately - meaning datalink signals are inhibited.

 

This missile is for use against enemy bombers (remember, most of the Russian planes are designed with homeland defense in mind) when the ECM is too heavy to use radar missiles. Bombers are /big/ IR targets ... from longer ranges than fighters. Much longer - and nowhere near as evasive. Plus it's a fire and forget missile.

[tflash]

Because it doesn't. That's all there it to it.

 

 

Sometimes the truth is simple ;)

[GGTharos]

Sometimes yes, very much so ;)

[nscode]

Me thinks you need radio signal processing for the datalink, that is shared with the guidance part in the radar versions. And you don't need them in the same time anyway - you are either getting the datalink, or homing onto the reflection.

 

Maybe there wasn't enough space for both the IR seeker and the datalink electronics back then.

[GGTharos]

Or maybe the seeker just inhibits the DL since it comes online the moment yous elect the missile ... either way - the DLINK signal is apparently not generated by the WCS, just as it isn't generated for the R-73.

 

Me thinks you need radio signal processing for the datalink, that is shared with the guidance part in the radar versions. And you don't need them in the same time anyway - you are either getting the datalink, or homing onto the reflection.

 

Maybe there wasn't enough space for both the IR seeker and the datalink electronics back then.

[Pilotasso]

By all means let the ET have data link and be carried in all Pylons of the Russian planes just because a few people think it makes sense and everybody else is an ignorant.

 

How many times weve been here?

[Alfa]

Sometimes the truth is simple ;)

 

Yeah it is :D .

 

As GG said there cannot really be any doubts left in regards to the nature of the R-27T/TE.

 

Why waste a long-range missile with only a short-range missile seeker?

 

Short range missile seeker? ;)

 

The 36T IR seeker is stated to have an acquisition range of ~ 10-15 km head-on, but up to some ~ 40 km in rear aspect against a fighter type target at full military thrust(non AB).

 

The 9B-1101K SARH seeker is stated to have a head-on acquisition range of ~25-30 km head-on against same type of target(RCS=3m2), but(being a radar seeker), a considerably shorter range in rear aspect.

 

In other words you could expect acquisition ranges for the two seeker types to be pretty much reversed depending on engagement aspect :) .

[Force_Feedback]

Nor does it have LOAL, the only LOAL missile in loomac s the heavily undermoddled MICA IR, which should have like god-like performance in both close combat as medium ranged. All LOPE MICA IRs, don't bother with ETs, those suck, and in real life, the R-27 has a crappy track record (the export versions, mind that). I also heard that during a live fire excercise an R-27R was used to intercept a stray SAM, than was coming at Mach 3 towards the launcher. Well, only 1 R-27R was needed to intercept that SAM, that's a ~6000 km/h closure rate. But again, this was a VVS R-27, not the R-27RE1

[Pilotasso]

Actualy the MICA has too much range In Lomac.

[tflash]

By all means let the ET have data link and be carried in all Pylons of the Russian planes just because a few people think it makes sense and everybody else is an ignorant.

 

How many times weve been here?

 

Sorry Pilotasso, but I did not claim such things. I said the reasons behind the R-27ET escaped me. I am an enlightened person now, after GG's explanation :D

[Pilotasso]

^^^^shock therapy :D

 

Not directed specificaly for you. :)

[mcnab]

 

The 36T IR seeker is stated to have an acquisition range of ~ 10-15 km head-on, but up to some ~ 40 km in rear aspect against a fighter type target at full military thrust(non AB).

 

I don't think it's possible to nail someone from behind with an ET if he's flying ABs at app. 30-40km, in LOMAC that is. Anyone actually tried this=?

[Alfa]

I don't think it's possible to nail someone from behind with an ET if he's flying ABs at app. 30-40km, in LOMAC that is. Anyone actually tried this=?

 

No probably not, but then the actual missile also needs to be able to chase down the target and thats exactly the idea behind the R-27T/TE.....namely that you can obtain better acquisition range via IR in tail aspect than with radar means, but that traditional IR homing missiles are small "dogfight" weapons without the energy to take advantage of this. Hence the idea to stick an IR seeker on a wacking big missile :) .

 

So although the R-27TE missile might not have enough energy to chase down a receeding target at 40 km, it is never the less a lot better equipped for this sort of engagement than an R-73 :) .