How EO and radar interact

[Gorn557]

Hello all:

I know I'm a bit past the peak of Su-27/FC popularity but hey, better late than never so I've been learning it. I am a bit confused over some of the details of how the mixed EORL locks work; it's not addressed in the manual and I've seen inconsistent answers on the forum. 

I understand that this is a mixed IRST/radar lock. My questions are:

1) I've gotten EORL to display on the HUD only by starting with EO off, then turning on EO when already in radar STT. If my EO is already on, and then I turn the radar on and go to STT, I don't see EORL on the HUD. In that case, am I actually in EORL even though it doesn't show on the HUD- e.g. if I drop radar lock because the target notches will it switch to IRST- or only if it's shown on the HUD? In other words is EORL something I have to specifically command or will it happen any time I have both radar and EO on and then lock on a target?

2) Does EORL work at all in conjunction with TWS?

3) As I understand it, in EORL the IRST is the primary sensor. I can think of something situations where this might not be preferable- is this always true, and are there tactical occasions when as a result EORL is not desirable?

Edited November 26, 2024 by Gorn557

[Ironhand]

The interaction in the two in the sim is a bit convoluted. In truth, you are never turning EOS “on”. You simply select it as the primary sensor by pressing “O”. With the radar, the same is true. Pressing “I” simply selects it as the primary sensor. When one is primary, the other is slaved to it.

When EOS is primary and a target is locked, the radar begins transmitting in quasi-search mode. When radar is primary, it is transmitting in either search or “TWS”.  When a target is locked with EOS, it tells the radar where to look for the target and vice-versa. The slaved sensor is always looking in the target’s direction.

There is something else involved as well. The selected missile type (IR vs radar seeker) will influence which sensor will become primary and demonstrate the interaction of the two systems. Start in EOS with an IR missile selected. Lock the target. Do not press “I”. Switch to a radar guided missile with the “D” key. EO is still displayed on the HUD. Press and hold the “launch” button. EORL will display as the radar locks the target and the selected radar guided missile will launch in STT.

Part of the problem in the sim is that only the primary system’s lock is displayed on the annunciation panel. In the real aircraft, both the primary and secondary (slaved) lock are displayed. So it can sometimes be harder to tell what’s going on in the sim.

Edited November 27, 2024 by Ironhand

[draconus]

17 hours ago, Ironhand said:

When EOS is primary and a target is locked, the radar begins transmitting in quasi-search mode.

Is it detectable by enemy RWR? I thought search and lock with just EOS and IR missile keeps you in "stealth" mode.

[Ironhand]

I may have misspoken there. I just reread that part of the manual. The radar transmissions are brief and intermittent and used to provide range information. In the real world aircraft, you have to move the radar transmit switch to transmit. Quasi-search mode (KVO) begins after a 5 second delay. So I suspect it’s detectable, when used.

In this mode, the radar system switches automatically from KVO to STT (RNP in transliterated Russian), when the range closes to 15 km or manually when the ENTER button on the flight stick is pressed at a greater range. So I don’t think KVO is modeled in the sim. In the sim, EOS just keeps the radar pointing at the target.

Edited November 28, 2024 by Ironhand

[AeriaGloria]

4 hours ago, draconus said:

Is it detectable by enemy RWR? I thought search and lock with just EOS and IR missile keeps you in "stealth" mode.

Not in DCS with EO lock. It’s not simulated that laser range is limited to about 3 km, and it needs 0.25 hz radar pulse above that range to get range (KVO mode mentioned by IH), only updated every 4 seconds. In game, it is as if laser has infinite range 

There are two lights on right hand instrument panel that turn on if radar or IRST is locked, though I am unsure if both can be on at once 

IMO, EORL has only one use case in game, in close combat mode search. While searching in close combat, It can use both and will lock with whatever gets lock first. 
 

In lock mode it seems to not matter other then not telling you which is primary sensor. In either RL or EO mode, if lock is lost and secondary sensor has lock, primary sensor switches. 
 

IRL this is different, I believe Ironhand can correct me, but I don’t believe there is a way to have a “both sensors looking and first to lock works” 

There will consistently always be a “primary/leading” channel/sensor and “Secondary/Slave” channel/sensor

If secondary gets lock first, depending on mode, it will not shows lock but only cue primary sensor until it gets lock then display it

IRL, As IH said, this primary or secondary sensor is  often chosen by position of selected mode, radar illumination switch, Laser designator, weapon selection of IR or radar missile, or gun mode activation

But in game it is entirely done by only selecting radar on/off or EO on/off 

[Hobel]

Am 26.11.2024 um 18:16 schrieb Gorn557:

Hello all:

I know I'm a bit past the peak of Su-27/FC popularity but hey, better late than never so I've been learning it. I am a bit confused over some of the details of how the mixed EORL locks work; it's not addressed in the manual and I've seen inconsistent answers on the forum. 

I understand that this is a mixed IRST/radar lock. My questions are:

1) I've gotten EORL to display on the HUD only by starting with EO off, then turning on EO when already in radar STT. If my EO is already on, and then I turn the radar on and go to STT, I don't see EORL on the HUD. In that case, am I actually in EORL even though it doesn't show on the HUD- e.g. if I drop radar lock because the target notches will it switch to IRST- or only if it's shown on the HUD? In other words is EORL something I have to specifically command or will it happen any time I have both radar and EO on and then lock on a target?

2) Does EORL work at all in conjunction with TWS?

3) As I understand it, in EORL the IRST is the primary sensor. I can think of something situations where this might not be preferable- is this always true, and are there tactical occasions when as a result EORL is not desirable?

 

Am 28.11.2024 um 14:50 schrieb AeriaGloria:

IMO, EORL has only one use case in game, in close combat mode search. While searching in close combat, It can use both and will lock with whatever gets lock first. 

Not only, if you shoot a Fox1 and the target notches your radar, the system falls back to EO and thus keeps the lock and CW on the target and thus the FOX1 can still track and hit the target.

[AeriaGloria]

Just now, Hobel said:

 

Not only, if you shoot a Fox1 and the target notches your radar, the system falls back to EO and thus keeps the lock and CW on the target and thus the FOX1 can still track and hit the target.

Does this actually happen? It will guide R-27R when it says EO? in DCS? 
 

Still means there is little to no reason for “EORL/TPRL” mode 

[Hobel]

vor 8 Minuten schrieb AeriaGloria:

Does this actually happen? It will guide R-27R when it says EO? in DCS? 

Yes, it works very well in dcs.

 

If you fire missile normally with radar and lose the lock, switch it to EO lock if possible and EO will then steer CW.  R and ER

[AeriaGloria]

9 minutes ago, Hobel said:

Yes, it works very well in dcs.

 

If you fire missile normally with radar and lose the lock, switch it to EO lock if possible and EO will then steer CW.  R and ER

I will give it a try! 

[AeriaGloria]

On 12/8/2024 at 10:34 AM, Hobel said:

Yes, it works very well in dcs.

 

If you fire missile normally with radar and lose the lock, switch it to EO lock if possible and EO will then steer CW.  R and ER

I tested this. I couldn’t fire and just turn on IRST and turn off radar 

However it would work if it automatically switched to EO/TP upon lost lock, such as notching 

Target would still be covered by radar lock symbol (in MiG-29), so radar still active, but HUD showing only TP/EO 

However, if missile was farther then about 2-9 km, it would not work. Sometimes it would acquire at 2-9 km then lose it right before hitting. Sometimes it would just never acquire. Sometimes it would acquire at 9 km and guide the whole way with TP/EO. Extremely random 

 

Edited December 12, 2024 by AeriaGloria