R-27ER update?

[Fri13]

Fir13, I think the labeling of the graph is just a little weird, and range and distance are just the x- and y-components of the distance vector to the target from a top down view.

 

Basically just read it like the R-27 chart above.

 

Even then it doesn't make any sense graphically, because you have LEFT/RIGHT sides that doesn't matter. In the R-27 graph it is split half because it doesn't matter is target your left or right.

 

The labeling is what makes it just odd, and then when you don't have any degrees there, you need to use ruler to actually find some.

 

 

Also note how the 40k ft co-altitute chart of the Aim-7 is a perfect circle with a ~22nm radius until the target aspect is about ~50°, which shows the seeker limitation. Only when the target aspect is above the ~50° the launch range is reduced due to energy limitations.

 

Yes, but that is again very confusing that why are you having a graphic that is combining the kinetic/aerodynamic capabilities AND then seeker limitation?

 

Again, doesn't make sense at all without textual information.

 

 

As anyone can see. Based to that graph the AIM-7 still has far better range when the target is about 30-60 degree angle, and it has shorter direct head-on distance.

Now if that would be just the kinematic range, it could be understandable that 0 degree is always better.

 

If it is RCS based, then it is understandable that 30-60 degree could be actually better as you should have a higher return from that angle than from 0 degree. And strongest should be then from 90 degree side angle, as target is largest in that.

But again the graph says that range from 90 degree angle is much shorter than what is the 30-60 degree, so it can't be RCS based but it should be kinematic one as of course 90 degree launch range is much shorter than 0 degree one.

 

Now the another challenge is the rear shots, 90-180 degree angles. Where again it goes correctly by the kinematics that 180 degree should be shorter than example 120 or 150 degree shots. And RCS should be more challenging against same speed target.

 

But this time again if we talk about RCS where your radar moves at same speed as your target, can your radar keep lock on the target when it is in the notch, or when it is beaming in perfect 90 degree angle? To the missile it doesn't matter really do you have a lock or not as you can just flood the target and missile flies far faster than the target at Mach 2 so relative to the missile radar the target is most of the time slower or faster and only in very specific moments when the missile speed match the Mach 1.95-2.05 scale the target would be notched.

 

The R-27 graph is very easy to read and understand.

 

 

The R-27 graph doesn't say anything about RCS, so it must be about just pure kinematic launch range on target at those two speeds, where faster gets always further and slower shorter. Higher always further and lower always shorter.

[Fri13]

R-27 family is currently terribly undermodelled, practically useless for both kinematic and sensor reasons (chaff and flares).

 

Yes yes, we all should know already that Chaff and Flare functions are from 90's and should change. The change should be coming as they are working with the radar features etc. We can only hope that chaff and flare gets complete overhaul...

 

ED is not in a hurry to do anything about it since AMRAAM equipped modules are the cash cows and multiplayer was never high on priority list (wake up, it is not 2001 any more)

 

Now that is a low blow... They have already stated that they are working with the missiles, and specifically stated that they are working with R-27 family as well.

And they very well know about the multiplayer part, they have been improving that part a lot in the years. What everyone who is flying in multiplayer should understand is that they are minority in the customer base. Their majority of the customers are in Single Player. But they are not forgetting multiplayer but improving that as well, like their own VoIP system, co-op flying etc etc.

So lets not drag again false accusations to their work. Okay?

[AnarchyZG]

Multiplayer is the future of everything, I have no idea about the current multiplayer/single player ratio.

 

Digression:

I can not understand why they're implementing their own voip. Their resources are limited and there are so many excellent standalone voip solutions. Even SRS if you want to simulate radio. Pointless waste of effort bringing nothing to online experience.

[Seaeagle]

 

http://eng.ktrv.ru/production/military_production/air-to-air_missiles/r-27r1_-_r-27er1.html

 

Type Range vs fighter type vs other (probably less manuverable, larger, slower)

R-27R1 50-60km <75km

R-27ER1 60-62,5 <100km

 

R-27T1 65km head-on

R-27ET1 80km head-on

 

Chart seems to be based on manufacturer's data for head-on launch ranges vs fighter type target at high alt, co-alt (30k, M0.9 parameters specified in the chart) for R/ER and head-on shots vs unspecified target for T/ET (presumably also high alt 30k feet).

 

Yes the chart is AFAIK from an aircraft manual and as such the recommended launch parameters for the operator(pilot), while the manufacturer's data are for absolute best case conditions(to make the product look as good as possible). The specifications for the -T/TE are clearly just the aerodynamic best range, since there is no way in hell you are ever going to be able to engage anything at 80 or even 65 km head-on with just an IR lock :) - so its basically the equivalent to the R/ER ranges for "other targets", where the shorter ranges specified for the T/ET are down to difference in aerodynamics(such as seekerhead).

 

Small difference between R/ER vs fighter type targets is interesting (maybe data link/illumination radar limit?) and kind of explains why russian fighters usually carry R-27R rather then ER

 

If radar power/datalink reach was the issue, it wouldn't explain why the range difference between R and ER becomes much more pronounced at longer ranges against non-maneuvering targets.

 

It probably has more to do with difference in motor configurations. The R has a boost-only motor, while the ER has a two-stage boost-sustain motor.....the second sustain stage is "weaker" and may only contribute moderately to range against a maneuvering target, but comes into its right when the missile is "cruising" at high altitude towards a non-maneuvering one.

[jasonbirder]

I have no idea about the current multiplayer/single player ratio.

 

 

Its Single Player>>Multi-Player (IE: Single Player is many times larger than single player)

[GGTharos]

It probably has more to do with difference in motor configurations. The R has a boost-only motor, while the ER has a two-stage boost-sustain motor.....the second sustain stage is "weaker" and may only contribute moderately to range against a maneuvering target, but comes into its right when the missile is "cruising" at high altitude towards a non-maneuvering one.

 

 

It's a much faster missile (it's boost stage is quite powerful, and so is the sustain stage) but at the same time it's still stuck with the ~60sec TOF limitation.

[BlackPixxel]

Small difference between R/ER vs fighter type targets is interesting (maybe data link/illumination radar limit?) and kind of explains why russian fighters usually carry R-27R rather then ER

Do not read too much into that 60 vs 62,5km from that one website. For a rough idea of the kinematic difference just compare the DLZ chart for R-27R and R-27ER. There is a massive difference.

 

The seeker range does not matter in the R-27 launch chart because the R-27R/ER uses INS + radio corrections until it is in range to use its own seeker (it will use its own seeker when 25km to a fighter sized target). Still the chart is not the aerodynamic range either, it is just the allowed launch range for a shot with a decent kill propability.

[Fri13]

What is the range marked as red in that R-27ER graph?

 

 

It is mystical one, it is for 900 km/h target/launch speed, but it doesn't have any meaningful difference between 0 and 180 degree intercept. Just very slight, like 19 km vs 18 km, but it maintains almost that same range through all the angles?

 

As well it is interesting that in all altitudes (1, 5 and 10 km) the launch speed of 900 km/h will deliver slightly longer (~2 km) engagement range because the target is as well flying at 900 km/h. So alone that 200 km/h difference in 180 degree engagement gives R-27ER missile longer reach at 5 km and 10 km altitudes.

[Fri13]

The seeker range does not matter in the R-27 launch chart because the R-27R/ER uses INS + radio corrections until it is in range to use its own seeker (it will use its own seeker when 25km to a fighter sized target).

 

That is one of those things I see as problem in the DCS. Once the seeker goes active, it seems that missiles finds the targets immediately without any challenge. So while the F/A-18C radar is simulated with the beam FOV to actually find the target, the missiles doesn't seem to have anything like that. Instead they are like FC3 level where there is instant information of the target in their maximum range.

 

And this is something that makes the missiles so awful really, that you have a fighter with a huge radar size and high power, that can have difficulties to find a target even at those 20-30 km distances. But then a missile that goes active 10 nmi (18.5 km) from the target with a tiny radar (will find the target like nothing, even when the target is far from their flight path and they are not supported by any radar but needs to find their targets by themselves (AIM-120C launched in VISUAL mode).

 

Still the chart is not the aerodynamic range either, it is just the allowed launch range for a shot with a decent kill propability.

 

Those charts likely are just something multiple things combined by slapping them as one simple graph so that pilot doesn't need to think anything else than just look at the chart and say "Yeah, I have range and speed at altitude, launch!" and let the FCS just tell them when the fire and where to point the missile.

[GGTharos]

that can have difficulties to find a target even at those 20-30 km distances. But then a missile that goes active 10 nmi (18.5 km) from the target with a tiny radar

 

 

Ever considered actually computing some distances with the radar equation?

[Fri13]

Ever considered actually computing some distances with the radar equation?

 

Can you give example a AIM-120C-5 seeker instructors and electronics designs?

[BlackPixxel]

I doubt the middle half circle has any meaning. Could just be a mistake that was not discovered. The graph still looks hand drawn. Maybe the drawer took the wrong pen to draw the thin circles and then wanted to remove the circle later and forgot.

 

Such mistakes can happen, look for example here on the R-24 graph:

The lines on the bottom right for the different speed ratios (1.0 and 0.8 ) are swapped for the maximum speed head on engagement. The solid line should be dashed and the dashed one should be solid, like with the low speed engagement.

[Seaeagle]

It's a much faster missile (it's boost stage is quite powerful, and so is the sustain stage)

 

Yes but its also a much heavier missile - the launch weight is 100 kg higher, so it will need some of that extra boost thrust to accelerate. I also wonder how the extra weight and length of the missile affects its agility against a maneuvering target.

 

but at the same time it's still stuck with the ~60sec TOF limitation.

 

Yes but that doesn't really explain the negligible range difference between the -R and -ER against a maneuvering target - if guidance is the culprit, then why state a difference at all? :)

[Seaeagle]

Do not read too much into that 60 vs 62,5km from that one website. For a rough idea of the kinematic difference just compare the DLZ chart for R-27R and R-27ER. There is a massive difference.

 

Still it is the data submitted by Vympel :) - the website in question(Tactical Missiles Corporation) just passes on the information they got from the individual manufacturers.

 

The seeker range does not matter in the R-27 launch chart because the R-27R/ER uses INS + radio corrections until it is in range to use its own seeker (it will use its own seeker when 25km to a fighter sized target).

 

Yes but INS/radio correction is also "its own seeker" as this is a function of the homing head(9B-1101k) and, as GGtharos said, this isn't an endless feature - IIRC datalink support is limited to ~ 25 km from launch aircraft and a number of seconds of operation(cannot remember if its 60 sec though).

 

Still the chart is not the aerodynamic range either, it is just the allowed launch range for a shot with a decent kill propability.

 

Exactly.

[nighthawk2174]

I've heard its 55 seconds, so probably in the range of 55-60 seconds for both the R/T and ER/ET.

[BlackPixxel]

It is 60 seconds not 55.

[Fri13]

I doubt the middle half circle has any meaning. Could just be a mistake that was not discovered. The graph still looks hand drawn. Maybe the drawer took the wrong pen to draw the thin circles and then wanted to remove the circle later and forgot.

 

That I find little difficult to believe, as if you would type a mistake to technical information then you go back and you fix it. Even if it is written by typewriter, you paint over it or you even write the paragraph again and cut that piece over wrong one and go on.

 

Typists goes through all those data again and again. It is not like someone writing to a forum.

That is the same thing with the book writing where Editions are there to fix the found problems. So if you have historical book that is Second Edition, then it excludes all found mistakes and errors fixed that were found in first Edition (there are historians etc that release new editions from their books, not fixing any single error or mistake they have, because they believe they are right regardless the errors they have made).

 

When it comes to such important technical documentation, one could think that they are checked and designed with great accuracy. BUT, there is the high risk that they get to wrong hands or the information in them gets leaked, and they get filled with lots of false information etc purposely.

 

And if that graphc is from a export version, it likely has lots of information that is withdrawn and false information that is added.

 

But as we don't have the context of the graphic itself that is explaining how to read it and what each part means etc, it can be anything.

 

Such mistakes can happen, look for example here on the R-24 graph:

The lines on the bottom right for the different speed ratios (1.0 and 0.8 ) are swapped for the maximum speed head on engagement. The solid line should be dashed and the dashed one should be solid, like with the low speed engagement.

 

You mean the marked red are?

 

[BlackPixxel]

Yes, I think those should be swapped. The solid line should be the one with more range, as in the lower speed one.

[GGTharos]

Can you give example a AIM-120C-5 seeker instructors and electronics designs?

 

 

You can't make an assumption about the dish size? Ok, sure - assume a 6" dish. 5" if that's a problem for you. 1kw peak power is probably not going to be out of the question for that little microwave.

 

 

You can make a ball-park assumption 30% SNR gain for the particular antenna technology vs. parabolic.

 

 

Tighten those up if you don't like them, pretty sure you can google enough reliable sources to figure it out.

[GGTharos]

Yes but its also a much heavier missile - the launch weight is 100 kg higher, so it will need some of that extra boost thrust to accelerate. I also wonder how the extra weight and length of the missile affects its agility against a maneuvering target.

 

 

The E rocket is a pretty zippy rocket. It's FAST.

 

 

Yes but that doesn't really explain the negligible range difference between the -R and -ER against a maneuvering target - if guidance is the culprit, then why state a difference at all? :)

 

 

That's up to their assumptions. Maybe they're not the same parameters for the two statements.

[GGTharos]

Yes but INS/radio correction is also "its own seeker" as this is a function of the homing head(9B-1101k) and, as GGtharos said, this isn't an endless feature - IIRC datalink support is limited to ~ 25 km from launch aircraft and a number of seconds of operation(cannot remember if its 60 sec though).

 

 

IIRC the datalink operation time is pre-computed for the given launch distance to cover a certain portion of the TOF, after that it assumes the seeker has taken over. The missile's operating time is 60sec according to the manual, though I've seen graphs for slightly longer times for the ER.

[Fri13]

You can't make an assumption about the dish size? Ok, sure - assume

 

Yeah, you do the assumptions....

[GGTharos]

Ok, it's obvious that this topic isn't for you. You have to be willing to do some reasonable work, and you're obviously not.

[AnarchyZG]

The specifications for the -T/TE are clearly just the aerodynamic best range, since there is no way in hell you are ever going to be able to engage anything at 80 or even 65 km head-on with just an IR lock :) - so its basically the equivalent to the R/ER ranges for "other targets", where the shorter ranges specified for the T/ET are down to difference in aerodynamics(such as seekerhead).

 

That is assuming T/ET has to acquire target with IR seeker at the moment of launch (LOBL). It would not make sense to design such a large missile and use it like R-73/Sidewinder.

 

Again, the chart shows recommended launch ranges vs fighter type target head-on aspect well above the range that IR seeker might be expected to obtain the lock so it is probably either autopilot or autopilot+datalink with terminal IR guidance.

 

Soviet BVR tactics supposedly recommended salvo launch T and R to make it more difficult for the target to defeat missiles with two different guidance methods (makes sense, vs R you want to turn and run on afterburner, but then you're presenting an ideal target for T with that 4 meter flame coming out of your engine). If you go head on/9-3 to minimize IR signature you're making it easier for R to hit you.

 

Other possible explanation theories were:

- T/ET only for tail chase rear aspect of fast fleeing targets (rather specific scenario, not very likely)

- rear aspect shots because of seeker/radar issues on early models vs targets going cold (medium PRF).

 

P.S. I wouldn't be surprised if some R-27R/ER were upgraded with active seekers and sneaky Russians not telling us about it. R-27 family is highly modular design

Edited March 2, 2020 by AnarchyZG
added info/opinion

[BlackPixxel]

R-27T/ET have INS but no datalink (no datalink antennas visible at least compared to R-27R/ER). So they can be fired at a head on target from long range using lock on after launch as long as the target does not maneuver to much. This procedure is explained in the manuals.