Tactics Against PD Radar in Mig-29 and Su-27 - ED Forums
 


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Old 05-18-2018, 05:40 PM   #1
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Default Tactics Against PD Radar in Mig-29 and Su-27

The pulse-Doppler radar that the Soviet Union put in Mig-29 and Flanker could only track targets if there was closure or extension. If you were heading at a PD radar then you turned 90 degrees and flew parallel to it, the PD radar would fail to show you as a radar contact.

I was just curious if you could use this tactic against the FC3 Mig-29, Su-27/33 with the intended effect or if accurate PD radars aren't modeled in the FC3 jets, or if the radars in the Russian FC3 jets are upgraded variants compared to what was in late Soviet era Fulcrums and Flankers.
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Old 05-18-2018, 06:56 PM   #2
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You certainly can. The doppler notch is very much modelled. That being said, any MiG-29 or Su-27 pilot who's worth a pinch of salt won't simply barrel in towards a target, particularly after launching, but will launch & crank to help prevent doppler notching. If you're flying against one, watch carefully what the intercept angle really is, and the enemy velocity vector, and change your flight path to suit otherwise you won't notch successfully and will still be visible.
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Old 05-18-2018, 07:18 PM   #3
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I also read that the early radar in Soviet Flankers and Fulcrums could only pick out the lead jet in a formation and was unable to differentiate between the lead jet's wingmen. Is that also modeled in the Flankers and Fulcrum?

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Old 05-19-2018, 12:36 AM   #4
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Originally Posted by chappingbrillopad1 View Post
I also read that the early radar in Soviet Flankers and Fulcrums could only pick out the lead jet in a formation and was unable to differentiate between the lead jet's wingmen. Is that also modeled in the Flankers and Fulcrum?
Yes it is modelled. I just did a very quick & dirty test. I was flying an Su-27 against 4 x F-15C's. We were all at 5,000m altitude way out over the sea to minimise and issues with ground clutter or reflections. Aspect was head-on. The AI 4-ship of F-15's were set to a close finger-4 formation which apparently means 50 metres separation. They were set up not to react to being locked by my radar.

I was able to pick up the enemy group as a single target at around 100 - 120 Km. The 4-ship single target resolved in to 4 separate targets at somewhere between 85 -90Km range. It should be noted that this was WAY beyond effective missile launch range. Note that there appears to be a strange anomaly here in that the enemy flight resolved in to discreet targets on my head-down display before they did on my HuD radar target display. So, in your case, if an enemy pilot is paying attention to their HDD, which all Su-27 pilots should be doing but fewer seem to do, they may be able to resolve a flight of 4 in to individual targets at anything up to 100Km, again for a head-on aspect engagement.

The MiG-29 has a less powerful radar than the Su-27 so the ranges I found would probably be reduced by anything between 25-40% if the enemy is a MiG-29.

I'd say the take home is that for any reasonable separation of a 4-aircraft flight, an enemy Su-27 will be able to resolve individual targets at anything up to 90 Km, assuming head-on aspect & no ECM. This range will be less for if you're part of a fingertips formation, but if you're going in harms way you should probably be combat spread anyway.
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Old 05-19-2018, 10:28 PM   #5
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Quote:
Originally Posted by chappingbrillopad1 View Post
The pulse-Doppler radar that the Soviet Union put in Mig-29 and Flanker could only track targets if there was closure or extension. If you were heading at a PD radar then you turned 90 degrees and flew parallel to it, the PD radar would fail to show you as a radar contact.
I think this is complete nonsense. Its true that when operating in "Encounter"(high PRF) search mode, the radar needs sufficient closure rate to see contacts, but own aircraft is not stationary so this would concern contacts that are receeding at the same or higher speed than your own.

This does not affect other modes that use medium PRF or a mix(interleaved) of medium/high PRF.

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You certainly can. The doppler notch is very much modelled.
"doppler notch" occurs when the target momentarily appears to be stationary and is filtered out as clutter - simply flying on a perpendicular course to the radar won't do by itself. Besides, it affects any PD aircraft radar - not just the Russian ones

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I also read that the early radar in Soviet Flankers and Fulcrums could only pick out the lead jet in a formation and was unable to differentiate between the lead jet's wingmen.
That is true - the radar might actually see aircraft in a formation as individual contacts and display them as such on the HUD, but will only allow the lead contact to be selected.
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Old 05-20-2018, 01:21 PM   #6
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Doppler notch takes advantage of the velocity gate set in pd radars such as the n001 and apg-63 to filter out clutter. Inside this closure speed pd radars reject contacts as has been described in the Gulf when an Iraqi Mig25 performed a doppler notch against F-15s resulting in them losing track.
This is modeled in DCS.

With regards to being able to lock onto only a lead this is probably down to cell resolution in non aesa radars which limits singling out close formations from long range, this is not modeled in DCS so far.
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Old 05-20-2018, 02:11 PM   #7
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Quote:
Originally Posted by Alfa View Post
I think this is complete nonsense. Its true that when operating in "Encounter"(high PRF) search mode, the radar needs sufficient closure rate to see contacts, but own aircraft is not stationary so this would concern contacts that are receeding at the same or higher speed than your own.

This does not affect other modes that use medium PRF or a mix(interleaved) of medium/high PRF...
I'm not so sure about that last statement. From the real world manual:

Quote:
...

The Radar Aiming Complex (RLPK) provides detection of aerial targets flying with a speed of more than 210 km/hr in both Front Hemisphere (HPRF) and Rear Hemisphere PRF (MPRF). Targets flying at a lower speed (for example, a helicopter) are not detected. The Radar Aiming Complex supports the locking of slow moving objects like helicopters when locked using Front Hemisphere PRFs. The detection and locking of hovering helicopters and attacking using Rear Hemisphere PRFs is not guaranteed.

When attacking targets using Rear Hemisphere PRFs in a look-up situation at flight altitudes of more than 8500 m, the Radar Aiming Complex (РЛПК) provides the detection and capture of targets if the closure rate is greater than 300 km/hr. In the rest of the cases, when attacking with Rear Hemisphere PRFs, the RLPK supports the detection and capture of targets with closure rates of 180 km/h or more. This closure speed is reduced to 100 km/hr or more, when approaching from behind the target. In situations with little or no closure rate, detection isn’t provided.

Tracking of targets is provided when closing with a speed differential of no less than 150 km/hr. In order to maintain a specified speed during an attack using Rear Hemisphere PRFs, it is necessary to keep the closure rate marker (which is not represented inthe sim) centered between the zero closure rate and “own speed” marks. If the closure rate scale starts flashing, increase your aircraft’s airspeed.

...
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Old 05-20-2018, 05:27 PM   #8
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Quote:
Originally Posted by Ironhand View Post
I'm not so sure about that last statement. From the real world manual:
You wrote speeds for autotracking in SNP. The minimal closure speed for locking target is 60km/h or 50km/h if target is making 180 turn (front to rear hem.).

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Old 05-20-2018, 06:02 PM   #9
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Quote:
Originally Posted by Ironhand View Post
I'm not so sure about that last statement. From the real world manual:
This is interesting. Is there a complete English translation available?
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Old 05-20-2018, 06:17 PM   #10
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Quote:
Originally Posted by Ironhand View Post
I'm not so sure about that last statement. From the real world manual:
No I can understand that - the text you quoted is not very clear and seems to contradict itself.

I think it would be necessary to find a better description of each radar mode, what they provide/limitations and how they are used.
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