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Author Topic: Mikoyan MiG-23 Avionics  (Read 77980 times)

Offline Miguel Aresta

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Re: Mikoyan MiG-23 Avionics
« Reply #105 on: June 26, 2014, 11:15:17 am »
Does anybody have info on the AVM-23 analog computer ?

Offline SPuitH

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Re: Mikoyan MiG-23 Avionics
« Reply #106 on: March 09, 2016, 11:09:45 am »
Gents,

We're having an interesting discussion on ACIG regarding the use of the R-24R on the MiG-23MF.

Is the MiG-23MF capable of using the R-24R despite the fact that it has a different radar than the MiG-23ML?

Thanks in advance!

Regards,

Sander

Offline PaulMM (Overscan)

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Re: Mikoyan MiG-23 Avionics
« Reply #107 on: March 09, 2016, 11:37:26 am »
I believe not. It wasn't even the first Sapfir-23ML (323ML) which added R-24 compatibility but the upgraded Izdeliye 324ML.
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Offline SPuitH

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Re: Mikoyan MiG-23 Avionics
« Reply #108 on: March 09, 2016, 12:15:41 pm »
Thanks Overscan!

Had a hunch that this was the case, too.

Kind regards,

Sander

Offline crossiathh

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Re: Mikoyan MiG-23 Avionics
« Reply #109 on: March 10, 2016, 02:20:52 am »
Interesting question. Theoretically I see no problem to use the R-24 with the MiG-23MF.

Talking about the German LSK/LV MiG-23ML, which was delivered with the N003E and the R-23R/T (the R-24R/T was not delivered before 1986):
The first delivered batch of the German MiG-23ML was not "R-24 ready", the later (1985) was.
The difference was however, that the AVM-23 of the weapon system of the first batch MiG-23ML did not had the necessary parameters of the R-24 (Dmin, Dmax, Heading etc...) ready, to exploit the full capabilities of the R-24 (basically the better range, the better ECM was an advantage of the RGS-24 seeker of the missile) and the R-24 was treated like a R-23. One have to say, this never happens with the German LSK/LV.
The later batch AVM-23 already had this parameters right at delivery and the first batch MiG-23ML's AVM-23 were tuned to recognize the R-24 later on in the squadron. Finally all German MiG-23ML were capable to use the R-24 to full extend. Additionally you need the APU-23M1E, because you could not use the R-24R with the former APU-23M. That's it.

In turn this could mean that there should be no basic problem to use the R-24 with the MiG-23MF as long as you have the APU-23M1E launch rail attached and the missile would be recognized and used as a R-23. I don't know if the AVM-23 of the 323E could be modified for the R-24 parameters, but I asked a former German LSK/LV weapon specialist and I hope to get an answer.

However, IMHO the more important question is: If an air force have MiG-23MF and MiG-23ML/MLD and a stock of both missile types, does it really make sens to use the R-24 with the MiG-23MF?!

Offline PaulMM (Overscan)

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Re: Mikoyan MiG-23 Avionics
« Reply #110 on: March 12, 2016, 02:38:49 am »
Maybe, though it working with 323ML doesn't necessarily mean it would work with 323E in a MiG-23MF. You wouldn't get any range benefits, but it might be possible.
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Offline Gorka L Martinez Mezo

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Re: Mikoyan MiG-23 Avionics
« Reply #111 on: August 16, 2016, 03:19:11 am »
I don't know if anybody else has read Osprey's Duel 72 F-15C vs MIG-23/25 by Douglas Dildy&Tom Cooper. While the overall quality of the Duel series is highly variable, I was quite surprised by the description made by the authors about the MIG-23ML "Flogger-G" and its RP-23MLAE Sapfir III (N003E). Here's an excerpt from the book:
"For this version, the Sapfir had been redesigned for engaging only airborne targets in the “front quarter” (head-to-head). The radar had no capability for detecting or tracking targets it was chasing (i.e. the “rear hemisphere”)"

On rear engagements:

"Because the Sapfir III was designed exclusively for front-quarter intercepts and R-24R employment, the TP-23 IRSTS was provided to allow MiG-23 pilots to engage targets in their “rear hemisphere.” In a “stern chase” look-down scenario the TP-23 could locate a high-speed, afterburning (i.e. thermally “hot”) target ahead and the S-23 system would “slave” the seeker head of the IR-guided R-24T, the lock-on being indicated by an aural tone in the pilot’s headset. Range determination was, however, problematic and exacerbated because, in the “tail chase” mode, the R-24 had significantly reduced range, depending on the MiG’s overtake airspeed."

Comments anyone? Undoubtly this is a major limitation.

On the "look down" capability:

"For closing targets at or above the “Flogger’s” altitude, the radar could track (“lockonto”) a target inside 18.9nm (35km), which was approximately the maximum range of the R-24R missile when fired head-on at high altitude. To detect targets below the radar’s altitude, the AVM-23 computer used an “external coherence method” to detect a target passing across/through the “clutter” caused by the earth’s radar return (called “moving target indicator”). This computer process had severe limitations due to numerous “blind zones” in multiples of the radar’s PRF, being able to only detect targets in the duration between successive pulses, and was limited to much shorter detection ranges (16.2nm/30km)."

This seems similar to the Cyrano IVM "Look down" system, which, accoding to the pilots I`ve met, was quite unsuccesful.

Offline Pit

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Re: Mikoyan MiG-23 Avionics
« Reply #112 on: August 28, 2016, 12:12:49 pm »
Hi Gorka,

You can find the details you require in this same thread, page 1, the details are from MiG-23ML's weapon systems manual as provided by the user Mr. Detonator, nearly 10 years ago.

Quote
The weapon system selector switch “SIST” with modes:

-RL (BSV, BSV - Delta H4, BSV - Delta H1, SMV, MV)
-BS (I BS, II BS, III BS)
-T (T I, T II, T III, T – Phi 0-I, T – Phi 0-II)
-NVG

The switch IZL-EKV-VYK, impulse transmitter  (emit/equivalent/off)
The switch NAVED-AVT-RUCHN, the GCI datalink ARL-SML on/off
The switch MSKC-PPS-ZPS, low-speed target engagements/front/rear hemisphere 
The switch PU-VYK, parametric amplifier ON-OFF

The modes BSV, BSV-delta H4, BSV-delta H1, SMV, MV are switched automatically according to aircraft altitude Hs (DV-30 barometric sensor) and the antenna position ”Delta H” switch. The modes I BS, II BS, III BS must be switched manually. When the switch NAVED AVT/RUCHN is set to AVT, the radar mode selection is done automatically by GCI command link  (ARL-SML). The radar scan patterns under GCI are better optimized due to PPS/ZPS aspect. The one-way commands from GCI are displayed on special symbol indicator on the HUD sight. Pilot can interrupt the GCI anytime setting the switch to RUCHN.

The mode BSV for high/medium altitudes, all-aspect intercepts (Hc<>=Hs), pulse width ~4 µsec, PRF 1Khz, switching altitude Hs>4,5km, Beam width in search 2,5°. Scan patters depend on NAVED AVT/RUCH switch position. Beam width in STT  1.7°.

The modes BSV-delta H4, BSV-delta H1 for high/medium altitudes are useful for searching targets on earth background not using the Doppler shifts (MTI). For all-aspect intercepts, switching altitude is 4.5km>Hs>1,5km. It uses half/third PRF compared to BSV mode.  The “differential compensator device” (DKP) filters false ground signals out. For greater search range the parametric amplifier can be switched on. The receiver sensitivity gains of 5-10% (dB/mW).

The modes BS (I BS, II BS, III BS) for high/medium altitudes are used for all-aspect intercepts (Hs<>=Hc) in case of false targets (clouds) and for picking up targets on earth background by using reference coherent signal received by radar side-lobes. The “III BS” mode has the largest search range of 65km, the “I BS” the smallest one of 27km. The most used mode is the “II BS” with 45km search range. The "III BS" mode works only as a search mode. The FFT Doppler filtering techniques are used to select moving targets flying on the earth background.  The so-called “blind speeds” are overcome by changing PRF pulses during each scan line. More than 90% of “blind speeds” are covered, what ensures good MTI.

The mode SMV for medium/low altitudes, only rear-aspect intercepts (Hs<Hc), The switching altitude is Hs<1.5km, pulse width ~1 µsec, PRF 1Khz. The scan patters depend on NAVED AVT/RUCH switch position.

The mode MV is used to engage targets flying at low altitudes on the earth background. It is only for rear-aspect intercepts (Hs>Hc), The switching altitude Hs<1.5km, switch “Delta H”<0, pulse width ~1 µsec, Beam width in search 2,5°. The MV mode uses the MTI based on Doppler shifts.

Do you recommend the afore-mentioned book?

Offline Pit

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Re: Mikoyan MiG-23 Avionics
« Reply #113 on: August 28, 2016, 12:16:04 pm »
As far as I know, the AVM-23 electro-mechanical computer controls the weapon engagement zones calculations for the employment of the missiles and guns, and is not related with the signal processing of incoming radar signals, as it is not a digital signal processor, the radar itself relies on a bank of physical Doppler filters in the radar-receiver device for that.

Offline PaulMM (Overscan)

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Re: Mikoyan MiG-23 Avionics
« Reply #114 on: August 28, 2016, 01:46:34 pm »
The description by Dildy and Cooper is not really accurate to the best of my knowledge, however MrDetonator's post is specifically from a WarPac MiG-23ML manual and it is possible some of the modes listed were not available to the Iraqi MiG-23ML.

The MiG-23ML's radar had a lot of different modes and it was important to select the right one for the intercept geometry - pilot skill level was quite important.  With a skillful pilot, and a well-maintained radar, it was a reasonable system (though yes, not a true pulse-doppler radar). MiG-29's radar was much, much easier for the average pilot.

Its important to realise ALL radars tend to have best range against closing (head-on) engagements. Some early pulse-doppler radars do indeed only detect closing targets which I think is what Tom Cooper believes to be the case for the N003.
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Offline PaulMM (Overscan)

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Re: Mikoyan MiG-23 Avionics
« Reply #115 on: August 28, 2016, 05:32:00 pm »
Ahmad Rushdi said Iraqi MiG-23ML had Sapfir-23M radar in this topic many years ago.
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Offline Gorka L Martinez Mezo

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Re: Mikoyan MiG-23 Avionics
« Reply #116 on: September 02, 2016, 02:07:12 pm »
Well, I should have through the whole thread before posting again! :D In any case, I was quite dumbfolded by the information given on the book I made an "impulse post".

Hi Gorka,

You can find the details you require in this same thread, page 1, the details are from MiG-23ML's weapon systems manual as provided by the user Mr. Detonator, nearly 10 years ago.

Quote
The weapon system selector switch “SIST” with modes:

-RL (BSV, BSV - Delta H4, BSV - Delta H1, SMV, MV)
-BS (I BS, II BS, III BS)
-T (T I, T II, T III, T – Phi 0-I, T – Phi 0-II)
-NVG

The switch IZL-EKV-VYK, impulse transmitter  (emit/equivalent/off)
The switch NAVED-AVT-RUCHN, the GCI datalink ARL-SML on/off
The switch MSKC-PPS-ZPS, low-speed target engagements/front/rear hemisphere 
The switch PU-VYK, parametric amplifier ON-OFF

The modes BSV, BSV-delta H4, BSV-delta H1, SMV, MV are switched automatically according to aircraft altitude Hs (DV-30 barometric sensor) and the antenna position ”Delta H” switch. The modes I BS, II BS, III BS must be switched manually. When the switch NAVED AVT/RUCHN is set to AVT, the radar mode selection is done automatically by GCI command link  (ARL-SML). The radar scan patterns under GCI are better optimized due to PPS/ZPS aspect. The one-way commands from GCI are displayed on special symbol indicator on the HUD sight. Pilot can interrupt the GCI anytime setting the switch to RUCHN.

The mode BSV for high/medium altitudes, all-aspect intercepts (Hc<>=Hs), pulse width ~4 µsec, PRF 1Khz, switching altitude Hs>4,5km, Beam width in search 2,5°. Scan patters depend on NAVED AVT/RUCH switch position. Beam width in STT  1.7°.

The modes BSV-delta H4, BSV-delta H1 for high/medium altitudes are useful for searching targets on earth background not using the Doppler shifts (MTI). For all-aspect intercepts, switching altitude is 4.5km>Hs>1,5km. It uses half/third PRF compared to BSV mode.  The “differential compensator device” (DKP) filters false ground signals out. For greater search range the parametric amplifier can be switched on. The receiver sensitivity gains of 5-10% (dB/mW).

The modes BS (I BS, II BS, III BS) for high/medium altitudes are used for all-aspect intercepts (Hs<>=Hc) in case of false targets (clouds) and for picking up targets on earth background by using reference coherent signal received by radar side-lobes. The “III BS” mode has the largest search range of 65km, the “I BS” the smallest one of 27km. The most used mode is the “II BS” with 45km search range. The "III BS" mode works only as a search mode. The FFT Doppler filtering techniques are used to select moving targets flying on the earth background.  The so-called “blind speeds” are overcome by changing PRF pulses during each scan line. More than 90% of “blind speeds” are covered, what ensures good MTI.

The mode SMV for medium/low altitudes, only rear-aspect intercepts (Hs<Hc), The switching altitude is Hs<1.5km, pulse width ~1 µsec, PRF 1Khz. The scan patters depend on NAVED AVT/RUCH switch position.

The mode MV is used to engage targets flying at low altitudes on the earth background. It is only for rear-aspect intercepts (Hs>Hc), The switching altitude Hs<1.5km, switch “Delta H”<0, pulse width ~1 µsec, Beam width in search 2,5°. The MV mode uses the MTI based on Doppler shifts.

So I understand the radar (at least in this version, should have been capable to track a fleeing target? OF course, it MAY be possible the Iraqis had no access to the full ML radar modes as mentioned.

Quote
Do you recommend the afore-mentioned book?

The Osprey Duel series had great shifts on quality; in this particular case I wouldn't recommend the book. While it tries to get into hard data on weapon systems, it reallys doesn't clear many things up and, per the said comments on the radar systems, it looks like the info isn't too reliable.

Curiously enough, the F-15 systems are quite lightly covered.