missing evidence of error R-27ER and ET Terrible Performance

[PolarBear1606689440]

Hi, I was wondering if someone could fix the terrible performance of the current R-27ER and R-27ET missles??

[AeriaGloria]

What is wrong with them?

[PolarBear1606689440]

The shorter range they have now makes them uncompetitive at BVR, namely the R-27ER.  

[Temetre]

Maybe Soviets shouldve developed better missiles if they wanted to be competitive in DCS.

Jokes aside, DCS is trying to be realistic, and showing realistic missile performance. R-27s just arent that great; I thinks similar to modern Aim-7s at best. Best thing Russia/China has is R-77s, its like a worse Aim-120. I think Mig-29S and J-11 (chinese Su-27) can carry it.

And honestly, who knows if the R-77 isnt overperforming either. 

Edited May 18, 2023 by Temetre

[Hobel]

Am 16.5.2023 um 23:45 schrieb PolarBear1606689440:

Hi, I was wondering if someone could fix the terrible performance of the current R-27ER and R-27ET missles??

Loft the missle a bit that gives it a bit more range or more energy in the final approach

[PolarBear1606689440]

Thanks for the replies.  There is, however, another issue with the R-27ER, if the radar breaks lock and regains lock the missle does not track, unlike the Aim-7's.  

[Pavlin_33]

14 hours ago, Hobel said:

Loft the missle a bit that gives it a bit more range or more energy in the final approach

There's no loft on the Alammo. If you try to pitch up, the missile will just loose more energy trying to pull Gs.

[okopanja]

16 hours ago, PolarBear1606689440 said:

Thanks for the replies.  There is, however, another issue with the R-27ER, if the radar breaks lock and regains lock the missle does not track, unlike the Aim-7's.  

This change was introduced 2 patch versions ago. The reason behind the change is that SU-27SK manual (exported version later known as J-11A), explicitly states that if the lock is lost the missile is lost. This could be a limitation of the export version, but at the moment there is no better document source.

If you are flying redfor aircraft, it is highly recommended to learn more about radar and sensors and missiles in general. This way you would learn to utilize what you have while understanding the capabilities and limitations of both your own and opponent's weaponry.

In addition: altitude and speed have high impact on missile range. Find out what MAR (minimal abort range), notch, and crank are. Practice firing at AI equipped with superior weapons to find out how far you can go without getting hit. I am pretty sure you will then increase your odds against blue, since average blue player simply puts faith into the electronics to do the work for them. Against competent blue player you will have to think hard when to engage and when to run, while at same time exceeding his skills in order to win.

20 hours ago, Temetre said:

Jokes aside, DCS is trying to be realistic, and showing realistic missile performance. R-27s just arent that great; I thinks similar to modern Aim-7s at best. Best thing Russia/China has is R-77s, its like a worse Aim-120. I think Mig-29S and J-11 (chinese Su-27) can carry it.

China in game has PL-12 and SD-10, it would be interesting to see if the first one will be provided to J-11A. It would be a bold move on ED side (would cause lots of complaints from blue) but not unrealistic since these missiles were pictured on J-11As.

20 hours ago, Temetre said:

And honestly, who knows if the R-77 isnt overperforming either. 

The R-77 is actually under-performing at medium to high altitudes in supersonic range. Under these condition fins should perform the best. The modeled drag is to high so these missile have really modest range in game. We hope that future remodeling will fix this issue. However this missile remains to be one of the deadliest at close range and many people use it in this way.

 

Edited May 19, 2023 by okopanja

[Hobel]

vor 28 Minuten schrieb Pavlin_33:

There's no loft on the Alammo. If you try to pitch up, the missile will just loose more energy trying to pull Gs.

is that so?

loft.acmi straight.acmi

[Temetre]

vor 13 Stunden schrieb PolarBear1606689440:

There is, however, another issue with the R-27ER, if the radar breaks lock and regains lock the missle does not track, unlike the Aim-7's.  

Thats been mentioned before, apparently its how the IRL missile behaves.

vor 2 Stunden schrieb okopanja:

The R-77 is actually under-performing at medium to high altitudes in supersonic range. Under these condition fins should perform the best. The modeled drag is to high so these missile have really modest range in game. We hope that future remodeling will fix this issue. However this missile remains to be one of the deadliest at close range and many people use it in this way.

I was more thinking about the guidance and general capability. Even the Aim-120 has so little reliable data about it public, and I'd imagine the R-77 would be even harder to get any good data on. It seems like everyone is just saying "its like an russian equivalent to Aim-120", but thats such an incredibly vage statement.

Edited May 19, 2023 by Temetre

[okopanja]

14 hours ago, Hobel said:

is that so?

loft.acmi 36.99 kB · 1 download straight.acmi 35.06 kB · 1 download

You are correct in terms of end effect, but from pure technical point of view, this should not be called loft, and besides will usually work only in certain scenarios.

Before the change that roughly coincided with HOJ fix, ER had been a guidance law which I would describe as used a simplified proportional navigation with range dependent proportional factors.

After this change it appears the missile is actually using PID controller (proportional, integration, derivation factor). The guidance law defines the desired trajectory as a function. In case of the R-27 this is a straight line between missile and target. In case of AMRAAM/SD-10, depending on range this is either ballistic trajectory or direct line. What happens next is that PID controller measures the deviation from expected trajectory which is used to apply the correction based on P-I-D factors. Since R-27 originally had only P component(s), the end result was that any attempt at faking loft would result to immediate rapid correction and therefore rapid energy loss with no benefit. So back then we had to make sure we actually to but the dot into the circle. 

However, by selecting I and D component you can control how quickly the missile returns to the desired path and this is how lofting effect was produced with R-27ETER. It is worth to note that ET still uses the old system. so no lofting is recommended here.

Here is not too much technical explanation:

 

Edited May 19, 2023 by okopanja
Made minimal correction

[Hobel]

vor 44 Minuten schrieb okopanja:

You are correct in terms of end effect, but from pure technical point of view, this should not be called loft, and besides will usually work only in certain scenarios.

Before the change that roughly coincided with HOJ fix, ER had been a guidance low which I would describe as used a simplified proportional navigation with range dependent proportional factors.

After this change it appears the missile is actually using PID controller (proportional, integration, derivation factor). The guidance law defines the desired trajectory as a function. In case of the R-27 this is a straight line between missile and target. In case of AMRAAM/SD-10, depending on range this is either ballistic trajectory or direct line. What happens next is that PID controller measures the deviation from expected trajectory which is used to apply the correction based on P-I-D factors. Since R-27 originally had only P component(s), the end result was that any attempt at faking loft would result to immediate rapid correction and therefore rapid energy loss with no benefit. So back then we had to make sure we actually to but the dot into the circle. 

However, by selecting I and D component you can control how quickly the missile returns to the desired path and this is how lofting effect was produced with R-27ET. It is worth to note that ET still uses the old system. so no lofting is recommended here.

Here is not too much technical explanation:

 

Of course, this does not always work but if it is possible you can use it and depending on the situation you will get a good result.

 

My test was 20° loft in.

In past tests I have also tried others and depending on that the missle arrived at the target with the same conditions also with 1.0M more, which is quite clear.

[Pavlin_33]

14 hours ago, Hobel said:

is that so?

loft.acmi 36.99 kB · 2 downloads straight.acmi 35.06 kB · 2 downloads

I am not 100% sure that this in deed is lofting. The missile pulls up to 3Gs in order to correct the path towards the target.
I could be wrong also.

[GGTharos]

14 hours ago, okopanja said:

This change was introduced 2 patch versions ago. The reason behind the change is that SU-27SK manual (exported version later known as J-11A), explicitly states that if the lock is lost the missile is lost. This could be a limitation of the export version, but at the moment there is no better document source.

Do not even attempt to hold on to that hope.   This is simply a characters of SARH missiles which must be deconflicted by radio channel to avoid EMI.  Once the track is lost, that radio channel is lost.

A radar that can drop the track (and I am being very specific about the wording, as the channel will be in some way attached to the track, either literally in software/hardware or coincidentally) and the resume guiding with the same channel after re-acquiring will the the exception and not the rule for AI radars.

If the AIM-7 does not behave the same way, then that is the bug, the AIM-7 should have the same behavior.  Track and radio channel go bye bye together.

[okopanja]

1 minute ago, GGTharos said:

Do not even attempt to hold on to that hope.   This is simply a characters of SARH missiles which must be deconflicted by radio channel to avoid EMI.  Once the track is lost, that radio channel is lost.

A radar that can drop the track (and I am being very specific about the wording, as the channel will be in some way attached to the track, either literally in software/hardware or coincidentally) and the resume guiding with the same channel after re-acquiring will the the exception and not the rule for AI radars.

If the AIM-7 does not behave the same way, then that is the bug, the AIM-7 should have the same behavior.  Track and radio channel go bye bye together.

Dude read carefully what I wrote here. there is an explicit line in the manual.

[Hobel]

vor 32 Minuten schrieb Pavlin_33:

I am not 100% sure that this in deed is lofting. The missile pulls up to 3Gs in order to correct the path towards the target.
I could be wrong also.

I thought it was also called loft when you give it manually with the plane, has that changed?

Tacview-20230520-000003-DCS.zip.acmi Tacview-20230519-235840-DCS.zip.acmi

[okopanja]

7 minutes ago, Hobel said:

I thought it was also called loft when you give it manually with the plane, has that changed?

For common flier: yes, this is loft. From the point of engineer: a rather interesting selection of proportional and dampening factors. If you look carefully into the graph it you will notice asymmetric shape of climb and descend section.

 

nullnull

 

[=BoB= David]

On 5/18/2023 at 9:32 PM, PolarBear1606689440 said:

Thanks for the replies.  There is, however, another issue with the R-27ER, if the radar breaks lock and regains lock the missle does not track, unlike the Aim-7's.  

That is not true, depends on type of missile, if Fox 1 is guided by CW (like some types of Aim-7), it is possible to "lock up" target again and missile will guide correctly, because missile is guided by radar reflection from target, 27s using different principle of missile guiding.

[Pavlin_33]

54 minutes ago, =BoB= David said:

That is not true, depends on type of missile, if Fox 1 is guided by CW (like some types of Aim-7), it is possible to "lock up" target again and missile will guide correctly, because missile is guided by radar reflection from target, 27s using different principle of missile guiding.

27 is also homed in to target's reflection when it reaches 80% of flight path.

[GGTharos]

2 hours ago, =BoB= David said:

That is not true, depends on type of missile, if Fox 1 is guided by CW (like some types of Aim-7), it is possible to "lock up" target again and missile will guide correctly, because missile is guided by radar reflection from target, 27s using different principle of missile guiding.

There's no reason to believe this to be true for any modern-ish radar.  CW also requires separate radio channels for deconfliction.

[ShadowFrost]

Also for the record, the PRF change shouldn't effect anything unless host radar lock is lost. I ran something like ~780 tests to regression test this and there was no difference between the old and new missile on release for fully supported shots. 

However, if you have a scenario you believe that it isn't functioning in the same way, I am more than happy to take a look and compare again, because something could have changed. But for the moment, a decrease in PK is only expected if the host radar loses lock. Past that, it should be the same as before. 

Edited May 20, 2023 by ShadowFrost