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Ракеты в DCS


Chizh

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@Маэстро

Hello,

 

What are the plans for development on the R-27? They fail to achieve the numbers on the official charts at 1.000m, and as i showed in DM they even fail to do so at 10.000m of altitude.

This is now especially worse due to the range reduction at low altitude mentioned in your recent newsletter.

On the non-kinematic front, there is of course the bug with the missile maneuvering when lock is lost. It would be interesting to hear about the progress on that too.

Thank you in advance.


Edited by Max1mus
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.....

 

And it was like this....

 

There is one old project rocket from late 50's of last century, it's interesting because for this one everything is available, from geometrical features to plenty of diagrams and of course Cx functions included. Not only project data but also results confirmed in live tests. And size is comparable to R-27R, this one was in calibre 280mm.

Drawn in scale together with R-27R with estimated measures is for comparison. Wings of R-27 are really huge, bigger then what I used yesterday so after taking some more papers and calculator I got slightly higher values.

 

Graph is of all three together with reference area of this antique one (0,0615m2). Red one is yours, green my calculation. Close, either green will get up a bit or red will get down a bit, but difference is very acceptable. All in passive, green at 10km altitude.

This 10% difference gives me nothing more then to say that as much as per me, I think Cx function of R-27R that you applied is very correct and very very close to real state. Even those genius form 50's and 60's had significant deviations between calculated and measured in flight. Some digits down or up is fair by all means.

 

I hope I'm not boring too much with this, it's just very interesting theme to me...and now I'm out...hope this time computer will not eat my words 

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14 часов назад, Jack1nthecrack сказал:

Hi Chizh,

Is there a possibility of reducing the CCM value for the R-27ET, currently it is easily defeated with only a few flares. Two flares is enough to defeat it. This cannot be realistic?

It depends on the target IR signature. If the IR signature is quite small, for example a MiG-21 in military mode, then a few flares will be enough to cover it. If the signature is large, for example a MiG-25 with afterburner, then a lot of flares are needed.

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It depends on the target IR signature. If the IR signature is quite small, for example a MiG-21 in military mode, then a few flares will be enough to cover it. If the signature is large, for example a MiG-25 with afterburner, then a lot of flares are needed.
Are flare rejection coefficients same for Aim9m vs 73/ET?

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В чейнджелоге прочитал интересную строчку касаемо модуля томкета а именно ракет феникс и аим-7 - 

  • Increased AIM-54 and AIM-7 RCS as per request from Eagle Dynamics. 

это значит что их проще обнаружить?

Летаю по священным скрижалям Хартмана

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31 minutes ago, BlackPixxel said:

MiG-29 manual says that the 73 can be used with active enemy countermeasures.

Yes and that's more of a consequence of its seeker being a modern cooled seeker with a small fov (giving it the ability to see skin heat reducing the amount flares pull the aimpoint) rather than any dedicated CCM circuits as per my current understanding of the tech in the RMD1.  

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2 часа назад, Breakshot сказал:

Why? Shouldnt 73 seeker fall somewhere between 9M and X? It is a more advanced weapon compared to earlier 9s...

Why do you think so?

1 час назад, BlackPixxel сказал:

MiG-29 manual says that the 73 can be used with active enemy countermeasures.

Any modern missile can be used with countermeasure conditions. The whole question is only in the hit probability. 😉

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1 час назад, Hunter2.1 сказал:

В чейнджелоге прочитал интересную строчку касаемо модуля томкета а именно ракет феникс и аим-7 - 

  • Increased AIM-54 and AIM-7 RCS as per request from Eagle Dynamics. 

это значит что их проще обнаружить?

Да. У многих радарных ракет мы немного увеличили ЭПР за счет того что сама антенна ГСН является отличным отражателем излучения.

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4 hours ago, nighthawk2174 said:

The 9M has dedicated CCM circuits where the RMD1 does not.

The R-73 RMD-1 Does have CCM, it just does not benefit from digital IRCCM techniques like introduced in the AIM-9M

Introduction to Modern EW Systems, Second Edition

By Andrea De Martino mentions this on page 324

 

This link also explains the mechanics of non digital IRCCM in a reticle seeker missile

https://dspace.lib.cranfield.ac.uk/bitstream/handle/1826/10981/Modelling_ultraviolet_threats-2016.pdf;jsessionid=B6D4D03ACE8ED17A9B57F792EDE4767E?sequence=3

the RMD-1 being around the AIM-9L / AIM-9M-2 CCM wise is a rather reasonable assumption

 

From what has been said from Russian SME's the 1995 RMD-2 did have better IRCCM capabilities and other sources say the only differences aside from improved gimbal limits are greater seeker lock range and slightly increased weight

(I assume this picture is from NASIC)

I don't believe this to have been as a result of a bigger motor, more CCM Circuits seem most likely

R-73 range table.png


Edited by TaxDollarsAtWork
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4 hours ago, TaxDollarsAtWork said:

The R-73 RMD-1 Does have CCM, it just does not benefit from digital IRCCM techniques like introduced in the AIM-9M

Introduction to Modern EW Systems, Second Edition

By Andrea De Martino mentions this on page 324

 

This link also explains the mechanics of non digital IRCCM in a reticle seeker missile

https://dspace.lib.cranfield.ac.uk/bitstream/handle/1826/10981/Modelling_ultraviolet_threats-2016.pdf;jsessionid=B6D4D03ACE8ED17A9B57F792EDE4767E?sequence=3

the RMD-1 being around the AIM-9L / AIM-9M-2 CCM wise is a rather reasonable assumption

 

From what has been said from Russian SME's the 1995 RMD-2 did have better IRCCM capabilities and other sources say the only differences aside from improved gimbal limits are greater seeker lock range and slightly increased weight

(I assume this picture is from NASIC)

I don't believe this to have been as a result of a bigger motor, more CCM Circuits seem most likely

R-73 range table.png

 

Right maybe I should clarify I don't consider the secondary effects of the linear array the R73 has to be directly comparable to dedicated CCM measures such as directly filtering out flares by various means.  It has a higher natural resistance than say a spin-scan seeker due to it having a small I-FOV but while the flare is in the I-FOV it is still just a susceptible as older seekers as it lacks any way to filter them out inside the fov.The RMD-2 though should be added to the game imo and should probably be in the ball park of more modern 9M's in terms of flare resistance.

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22 hours ago, nighthawk2174 said:

Right maybe I should clarify I don't consider the secondary effects of the linear array the R73 has to be directly comparable to dedicated CCM measures such as directly filtering out flares by various means.  It has a higher natural resistance than say a spin-scan seeker due to it having a small I-FOV but while the flare is in the I-FOV it is still just a susceptible as older seekers as it lacks any way to filter them out inside the fov.The RMD-2 though should be added to the game imo and should probably be in the ball park of more modern 9M's in terms of flare resistance.

While what you said is correct, its a more apt description of how IRCCM works in single colour Con Scan Frequency Modulated detectors. Take for example the AIM-9M/L (And broadly all late Sidewinders sans 9X) would use things such as flare deceleration (through LOS Rate change) to discriminate between the target and counter measures in the IFOV.

 

More processing and software obviously goes a long way with IRCCM in nutating seekers since its just as important to be able to accurately process what it sees.

 

But the R-73 family takes a slightly different approach, it is commonly described as a two colour pulse position seeker. I like to draw parallels between signal processing and power in radars (in this case a better missile 'front end' or seeker set up), one solution isn't nearly as good pound for pound but still does provided results.

 

Academically it has many different names, dual band seeker and Spectral Distribution Discrimination among other technical sobriquets.

I found that this paper "Expendable Countermeasure Effectiveness against Imaging Infrared Guided Threats C. R. Viau Tactical Technologies Inc., 356 Woodroffe Ave., Ottawa, ON Canada"

 

Explained it best simply as

 

"Spectral distribution discrimination is commonly referred to as two-color discrimination. Seekers equipped with dual mode detectors can view a scene in two separate bands of the spectrum. The seeker compares the spectral distribution ratio of the various targets in the field of view to a predefined threshold. If a target does not meet the two-color ratio criteria, it is classified as a flare and rejected as the true target. Early generations of flares produced a much different signature ratio than aircraft plumes and as a result were susceptible to two-color discrimination."

 

So while a wholly non digital IRCCM set up in the RMD-1 & 2 it was wholly adequate, actually beyond that for the flares of the time and era and Tek isn't exactly wrong to say in some ways it was a better seeker for the time.

 

The paper on its own is interesting as well as it covers the effectiveness of different types of flares working on slightly different principles to pull off seekers

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Great find, I recall reading this before.

 

Key words 'early generations of flares', and 'appropriate response'.

For example, for the sidewinder the intensity-rise-time technique would cease tracking (or coast) until the flare left either the FoV or part of it.  Effective but also defeatable by a good flare drop interval and maneuver as an example.  (Incidentally, if you recall the 'dirty flares' anecdote, this was apparently the problem - intensity-rise-time of them dirty flares was too slow - the IRCCM was corrected quickly to cope)

 

So, we can theory-craft all over the place but the fact is that we won't know flare effectiveness for real.


Edited by GGTharos

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4 minutes ago, GGTharos said:

Great find, I recall reading this before.

 

Key words 'early generations of flares', and 'appropriate response'.

For example, for the sidewinder the intensity-rise-time technique would cease tracking (or coast) until the flare left either the FoV or part of it.  Effective but also defeatable by a good flare drop interval and maneuver as an example.  (Incidentally, if you recall the 'dirty flares' anecdote, this was apparently the problem - intensity-rise-time of them dirty flares was too slow - the IRCCM was corrected quickly to cope)

 

So, we can theory-craft all over the place but the fact is that we won't know flare effectiveness for real.

 

Yes it is one of those aspects of DCS where the current system in some ways is good enough

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