R-27ER update?

Thanks! Interesting, for the typhoon it's suggested that the AMRAAM turns off the receiver once it has acquired (presumably this is referencing MPRF guidance).

So I wonder if AMRAAMs behave differently from aircraft to aircraft then, tracking logic wise.

An R-27 ignores ownship data once it is homing, although it will still receive link data if it loses track (the ownship radar does not) which is nice.

As far as I understood how it works, this is not possible. The radar sends either course correction signals (midcourse guidance phase) or target illumination signals once it expects the missile seeker to be in range and it had sent a command to the missile to switch on the SARH seeker.

@FoxAlfa

You could compare in game NEZ parameter vs the above video with the same bandit speed and aspect to see if they match.

I wrote to Chizh, he said that it looks like a bug and said they will check.

The most simple thing is R-27ET and R-27T engagement envelops out range the R-27ER and R-27R, which simply isn't possible since the T variants have a bigger drag due to a round nose.

It is continuously illuminating, and DL is provided if the launch distance is outside of the missile sensor's capture range (from the MiG). The missile decides when to use/not use the DL when it is being transmitted.

As for the missile re-acquiring with DL, maybe I'm misinterpreting what I'm reading:

The rocket also allows long breaks (up to 20-30% of the remaining pointing time) in the RLPK backlight while maintaining the time diagram of the backlight channel.

As far as I understood how it works, this is not possible. The radar sends either course correction signals (midcourse guidance phase) or target illumination signals once it expects the missile seeker to be in range and it had sent a command to the missile to switch on the SARH seeker.

It is continuously illuminating, and DL is provided if the launch distance is outside of the missile sensor's capture range (from the MiG). The missile decides when to use/not use the DL when it is being transmitted.

I'll have to search for those references again to refresh my memory, perhaps I remember it wrongly.

That's not possible AFAIK. From what I've read, the radar sends out target tracking signals, but these are not illuminating the target simultaneously.

I don't even know what that means. Once you're in STT, the radar is illuminating.

Either correction data or illumination data is sent interchangeably with the target tracking signal by the radar

DL is blended into the signal - and even if not, it all happens so fast that there's literally no point in making the distinction. HPRF pulses are on the order of 600/sec.

I don't even know what that means. Once you're in STT, the radar is illuminating.

 

DL is blended into the signal - and even if not, it all happens so fast that there's literally no point in making the distinction. HPRF pulses are on the order of 600/sec.

Not quite. Yes, once you're in STT, the radar antenna is emitting target tracking signals on one channel to maintain the radar lock on target. For the RLPK-29, this period is 20.48 ms. But, this signal is not illuminating the target for the SARH missile.

The target illumination signals (which used to be sent via a separate CW antenna on older systems) are sent via a different channel (which is also used for radio-correction data), but since there's only one transmitter antenna, they are sent interchangeably with the target tracking signals. The radio-correction or target illumination signal is sent with a period of 30.72 ms.

During the inertial phase (which happens if the target range is more than 1.5 times of the seeker range), this channel sends out correction data to the missile. Once the WCS determines that the missile should be close enough to the target by now, it switches to sending the illumination data via this channel and radio-correction data is no longer sent out.

The radar is always illuminating from the moment your pull the trigger (just to differentiate STT a bit from things that have to be done to support the missile - ie. using PRF the missile wants to see ie. HPRF vs MPRF). You're misinterpreting what you're reading :)

Once the WCS determines that the missile should be close enough to the target by now, it switches to sending the illumination data via this channel and radio-correction data is no longer sent out.

The radar is always illuminating from the moment your pull the trigger (just to differentiate STT a bit from things that have to be done to support the missile - ie. using PRF the missile wants to see ie. HPRF vs MPRF). You're misinterpreting what you're reading :)

Since I noticed that you've written 'from the moment the trigger is pulled' in the quoted part, I've edited the post accordingly; sorry for the earlier snarky remark.

I've seen a graph showing different periods for different radar modes. E.g. in search mode, the radar emits pulses with a period of 10.24 ms. Once a target lock is established, it emits the target tracking pulses (which are naturally different and more complex from the search pulses) with a period of 20.48 ms and once the missile is launched, another signal is interleaved with the target tracking signals with a period of 30.72 ms which contains either trajectory correction signal (in case there's an inertial phase) or target illumination pulses for the missile.

So, the main point of contention is whether the radar is illuminating the target during the inertial phase (when the radio-correction signals are being sent to the missile) or not.

I'll try to analyze the source reference they've used to see if I can dig if these are mutually exclusive or are sent in parallel as I was reading somebody's analysis on how the target illumination works here and the way it was written seemed to indicate it's either one or the other.

But, on inspecting one of the used references myself, I'm inclined to conclude that the radio-correction data (or support as you said) is mixed in between the illumination signals of this illumination period.

This might have been what you were aiming at, but you did throw me off the point you were making with the "Once you're in STT, the radar is illuminating." remark in the previous post.

ED, can we finely get an update for the R-27 family, it is awfully undermodeled in DCS as is...

Hello Chizh,

Thank you for the comment, I do agree that performance is close to the diagrams.

I was referring and probably not being clear, I do apologize, but can we get then the correction for the Lethal range for R-27R (calculation or missile performance I can't tell from this end), since it is lower than the R-27T which has lower aerodynamic performance.

Very interesting info on the R-27er over in the Heatblur f-14 section by Polychop developer borchi_2b:

First of all this is not about the R27ER, this is about some fictional behavior of the aim54a/c missiles. We have tested this in depth and have found this and some other bugs.

 

R27ER

yes some of the stuff seems to be magical, but in the end there are some bugs too. Opposing to what people believe, this missile, the r27er platform, is, in regards to one guy we have access to who was a su30 testpilot, well undermodelled and roughly hits the prottype specifics of 1980 time.

Specs about the real R27ER are as follows:

head on range on fast moving targets at an altitude of 30000ft+ is 125km+ when you go supersonic with speeds around 1.5m of the launching platform.

The 27ET has a range in the same specs of 115km roughly.

Both platforms are _INS guided like the aim54 platform and only use ion terminal flight thier seekers. Roughly 10sec before impact these missiles use thier seekers, which is controlled by the weapon avionics logic of the launching platform, which is controlled by datalink. I can not go to much into detail, but also the countermeasure resitance is very strong compared to what you see in DCS, which means, the 27Er is chaff resistant and also does the 27et has a seekerlogic that bans certain heat ranges of the flares of nato, cause they burn in a very specific heatrange.

The INS guidance of these missiles makes it possible for su27 and mig29 platfroms to shoot these missiles in TWS too. The max ammount of TWS targets differs and is dependand on the date of the radar build in the su27 family. So if we are speaking of tuning down the 27er and 27et, ok cool, but that is a different topic.

 

For me the topic of adding the 27er into the discussion about a aim54a/c bug, makes no sense at all. Lets focus on the bug. Thanks

https://forums.eagle.ru/showpost.php?p=3850200&postcount=17

Would be great if Chizh can comment on this info. If true, the R-27ER/ET would be really lethal missiles compared to current DCS implementation.

Would be great if Chizh can comment on this info. If true, the R-27ER/ET would be really lethal missiles compared to current DCS implementation.

There is one thing we need to have clear, we like it or not. ED dont want to simulate sensitive russian weapons being a russian company. This means, or rather I suspect that, even if ED is totally aware of much newer versions of the R27ER/ET family (With INS, retarget capability or any other fancy stuff) they want to stick to a 1980/90 era family of these missiles, this is, what we have now.

The R27ER family of missiles we have now is pretty close to what those systems where capable of doing in the 80s/90s, and that is all we got.

This bring up other problems that need a totally separate discussion, like why are we mixing red side with 80s equipment with 9x/120c equipped hornets in MP and more of that kind, but truth be said, all that boils down to mission design and server rules.

There is one thing we need to have clear, we like it or not. ED dont want to simulate sensitive russian weapons being a russian company. This means, or rather I suspect that, even if ED is totally aware of much newer versions of the R27ER/ET family (With INS, retarget capability or any other fancy stuff) they want to stick to a 1980/90 era family of these missiles, this is, what we have now.

 

The R27ER family of missiles we have now is pretty close to what those systems where capable of doing in the 80s/90s, and that is all we got.

 

This bring up other problems that need a totally separate discussion, like why are we mixing red side with 80s equipment with 9x/120c equipped hornets in MP and more of that kind, but truth be said, all that boils down to mission design and server rules.

Again, It would be great if Chizh can comment on brochi_2B - R-27ER/ET info. You are speculating about what Eagle Dynamics can and cannot do and thier reasoning behind their design decisions. You are also implying that this discussion somehow is linked to multiplayer balance? This thread is about simulation of the missile. Not about multiplayer or even singleplayer. Im quite sure most of us in this thread are only interested to know if R-27ER is simulated correctly. borchi_2b - another dev - states that the R-27ER/ET is undermodeled. (ins guidance, radio/data-link etc)

Chizh probably won't comment, and borchi's info is useless. Chizh has the actual DLZ (not just the graphs that are available to us) simulation from far more interesting sources than borchi will ever get. As for 'us', we certainly have plenty of access to the Su-27SK manual, including a bunch of (but not all) weapons employment, and in no case is there an engagement profile beyond 90km.

That probably has more to do with the Su-27's radar than the missile itself though. A Su-30 might be able to provide far more powerful illumination.

Given how they've simulated the Mistral I wouldn't trust much of anything they have to say about air to air weapons anyway.

MP balance does NOT enter into play here. If it did, flanker would still be able to equip the mythical R-27EA.

Does the R-27 have a datalink? Yep (better than in RL I'd say)

Does the R-27 have INS? Yep (though limited)

Does the R-27 meet the known DLZs? Yep

We can argue about guidance algorithms and chaff rejection, I suppose - those will be unclear to some extent.

Again, It would be great if Chizh can comment on brochi_2B - R-27ER/ET info. You are speculating about what Eagle Dynamics can and cannot do and thier reasoning behind their design decisions. You are also implying that this discussion somehow is linked to multiplayer balance? This thread is about simulation of the missile. Not about multiplayer or even singleplayer. Im quite sure most of us in this thread are only interested to know if R-27ER is simulated correctly. borchi_2b - another dev - states that the R-27ER/ET is undermodeled. (ins guidance, radio/data-link etc)

Either you dont know to read or you have reading comprehension problems.

Where do i imply this being linked to MP balance?

In fact I say "This requires a totally different discussion..." :/:/

I trust the chart posted by Chizh. If I could figure out what the x and y values are lol

I think it is very unlikely that this hand-drawn chart is still valid for late built R-27's, but these are propably not the ones that DCS is trying to replicate.

At least for hot targets the ranges in the chart are almost spot on in DCS.

I trust the chart posted by Chizh. If I could figure out what the x and y values are lol

it's the engagement envelope (range) of the missile on the head-on (left axis), side on (top axis) and escaping (right axis) target.

the full line is for the target traveling at 1100 km/h and the dotted line is for the target traveling at 900 km/h.

the blobs corresponding to the engagement altitude of 1km, 5km, 10km.

So per example, the range against a target traveling 900 km/h at 5km equal altitude head-on should be around 38km and for the same target side on around 17km.

I think it is very unlikely that this hand-drawn chart is still valid for late built R-27's, but these are propably not the ones that DCS is trying to replicate.

 

At least for hot targets the ranges in the chart are almost spot on in DCS.

The chart is from the russian language pilots manual for the Su-27SK as far as I can tell, I attached the on for the R-27R from the MiG-29 manual just for references

Interesting! I wonder why there is the speed difference of 200km/h in this chart between MiG and target?

Thank you FoxAlfa!