How to use HOJ in Su27?

[Picasso]

Hi

The su 27 manual says you can lock on to ecm jamming signal and use SARH aka r27er in HOJ mode. I have tried many times but i am not able to do it. Kindly can someone explain how to use this? 

Thanks 

N.B screenshot from manual is attached 

 

Edited January 30, 2022 by Picasso

[Northstar98]

1. Select BVR mode
2. RADAR on
3. Observe strobe on HUD - EDIT: As per Ironhand's comments, the target must be transmitting for you to see this, so in the advanced waypoint actions for your target, click add -> select 'Set Option' and look for 'ECM Using' and set it to always use or when detected or locked by a RADAR.
4. Slew acquisition cursor over strobe and press the lock button
5. RADAR should begin an angle-only-track (range denied)
6. Select R-27R/R-27ER
7. Fire

Take note however that in HOJ mode the R-27R/ER seems to use pure-pursuit guidance instead of proportional navigation (unsure why that is), which means it's more likely to miss (especially if the target changes aspect).

Su-27S_R-27ER_HOJ.trk

Edited January 31, 2022 by Northstar98
updated as per Ironhand's comment

[Ironhand]

What Northstar98 neglected to mention is that the AI ECM setting must be "always on" in the ME which is not the default setting. Of course, if it's someone online flying around with his ECM always on, happy hunting.

[Picasso]

Thanks for the reply. Sadly I dont see the continuous jamming probes. In my hud i see target dots and when i try to get a lock the strob appears for a a fraction of seconds and then go away. So i can't actually take a lock on the jamming probe. 

I have attached the track aswell. In the track you can see, when I get the lock, its not a radar lock, its the thermal lock. 

Thanks

su27_HOJ_not_working.trk

Edited January 31, 2022 by Picasso

[Northstar98]

14 hours ago, Ironhand said:

What Northstar98 neglected to mention is that the AI ECM setting must be "always on" in the ME which is not the default setting. Of course, if it's someone online flying around with his ECM always on, happy hunting.

Yes, I should've mentioned that my step 3 requires the AI ECM usage setting to always on or use when detected or locked.

Though even if it's set to only when locked, shouldn't the R-27R/ER transition to HOJ on its own?

EDIT, just did another test, with the ECM set to use only when locked, but I didn't get any jamming indications at all and I was able to track the target at lock range as normal.

4 hours ago, Picasso said:

Thanks for the reply. Sadly I dont see the continuous jamming probes. In my hud i see target dots and when i try to get a lock the strob appears for a a fraction of seconds and then go away. So i can't actually take a lock on the jamming probe. 

I have attached the track aswell. In the track you can see, when I get the lock, its not a radar lock, its the thermal lock. 

Thanks

su27_HOJ_not_working.trk 24.4 kB · 0 downloads

Try setting your target's ECM usage to 'always on' or 'use if detected or locked by a RADAR'.

You won't get the strobe unless the target is actually transmitting its ECM, which it won't by default unless its locked.

The problem in your track is that the RADAR is trying to track the target in both angle and range, but as soon as you lock, the target's ECM transmits which denies ranging information (noise jamming), which then breaks the lock. Then once the lock is broken, the target stops transmitting its ECM.

Edited January 31, 2022 by Northstar98

[FoxAlfa]

There are unfortunately two things that need to be fixed and are reported to improve the HOJ use:
- R-27 family uses pure tracking instead PN in HOJ mode, severely limiting its range (this will hopefully be fixed when the missiles get full CFD and move to new API/AP)

- STT mode is lacking 'AП' indication next to the HUD when you lock the target, before this was a less of the issue, but with Vipers and Hornets Jamming only when locked, this information gain lot in importance.

[Ironhand]

8 hours ago, FoxAlfa said:

- STT mode is lacking 'AП' indication next to the HUD when you lock the target, before this was a less of the issue, but with Vipers and Hornets Jamming only when locked, this information gain lot in importance.

You’re not supposed to have an ‘AП' indication when in РНП. At least it’s not indicated as existing for that mode in the real world manual. The indication, I suppose, is the lack of range information until you burn through.

Edited January 31, 2022 by Ironhand

[FoxAlfa]

4 minutes ago, Ironhand said:

You’re not supposed to have an ‘AП' indication when in РНП. The indication at that point is the lack of range information until you burn through.

[Ironhand]

Hmmm… competing manuals. It does show it for Search but not STT.

[FoxAlfa]

1 hour ago, Ironhand said:

Hmmm… competing manuals. It does show it for Search but not STT.

you are looking at the wrong section... you need the appendix of engaging jamming target... 

Edited January 31, 2022 by FoxAlfa

[Ironhand]

1 hour ago, FoxAlfa said:

you are looking at the wrong section... you need the appendix of engaging jamming target... 

 

Which, unfortunately, is an appendix I don’t have. It’s not even listed in the TOC. Yours is from the Su-27 manual?

Edited January 31, 2022 by Ironhand

[FoxAlfa]

9 hours ago, Ironhand said:

Which, unfortunately, is an appendix I don’t have. It’s not even listed in the TOC. Yours is from the Su-27 manual?

 

The picture is from the Yugo MiG-29, so export 9.12b, the pictures of the HUD are 9.13C as far as I can tell.

The both version of Su-27 I have are completely missing info on engaging Jamming targets (I guess it is limited not to give info on ECM and ECCM stuff).

Also, worth noting that in the MiG-29 manual the AP indication isn't noted or mentioned in STT part (Combat Employment)...

only stressed out and noted in the Engaging jamming targets part of the manual as important.   

[okopanja]

Does present ED implementation take into the account the manually supplied ranging information?

For practical purposes this is value between 25-50km?

I tried multiple time head on HOJ launches, with result that R-27ER simply overshoots very closely the target (straight flying jamming F-15C).

There was not a single time I managed to hit with it.

Edited February 1, 2022 by okopanja

[Ironhand]

10 hours ago, okopanja said:

Does present ED implementation take into the account the manually supplied ranging information?

For practical purposes this is value between 25-50km?

I tried multiple time head on HOJ launches, with result that R-27ER simply overshoots very closely the target (straight flying jamming F-15C).

There was not a single time I managed to hit with it.

 

I’ve never known it to have any impact on anything except antenna elevation. A manual range of 10km with an elevation of 1km will scan a different slice of the sky than a range of 80 and elevation of 1 will (which you already know).

I’ve only bothered to launch once HOJ and that occurred this morning as a test. The launch was at around 50km. It hit after altering its course. By that time, however, the target was within burn through range, though I had not transitioned to STT again. TRK attached.

ECM 1.trk

Edited February 1, 2022 by Ironhand

[okopanja]

On 2/1/2022 at 9:36 PM, Ironhand said:

I’ve never known it to have any impact on anything except antenna elevation. A manual range of 10km with an elevation of 1km will scan a different slice of the sky than a range of 80 and elevation of 1 will (which you already know).

In this mode, the range is provided by the pilot, I gather either based on information from AWACS, GCI or simply pilot's judgment.

I found it in the game's manuals (see first post):

Su-27 Manual, page 58:
 

Quote

The target range displayed in the HUD with an active AOJ lock is not measured by the radar but rather provided by the fighter pilot (e.g. according to instructions received by radio), with the default value 10 km. If the entered target range is longer than the range of the chosen missiles for this altitude, then missile launch requires either that the entered range is manually reduced with [RCtrl--] until the "ПР" symbol appears, or that launch authorization override is enabled with [LAlt-W].

Mig-29 Manual, page 52:

Quote

The target range displayed in the HUD with an active AOJ lock is not measured by the radar but rather provided by the fighter pilot (e.g. according to instructions received by radio), with the default value 10 km. If the entered target range is longer than the range of the chosen missiles for this altitude, then missile launch requires either that the entered range is manually reduced with [RCtrl--] until the “ПР” symbol appears, or that launch authorization override is enabled with [LAlt-W].

Also note that @FoxAlfadid post part of real manual where it states: 

Quote

In case the range information is not available, strobe should be set to the distance lesser than 50 km during the attack in front sphere, and less than 30 km during the attack on the read sphere.

Given the fact that angular positions of target are known, the provided distance is likely provided as a part of the firing solution for the missile.

Edited February 9, 2022 by okopanja
typo

[Ironhand]

1 hour ago, okopanja said:

In this mode, the range is provided by the pilot, I gather either based on information from AWACS, GCI or simply pilot's judgment.

…

Also note that @FoxAlfadid post part of real manual where it states: 

Given the fact that angular positions of target are known, the provided distance is likely provided as a part of the firing solution for the missile.

 

Like I said, I’ve never known it to have an impact on anything except the antenna elevation. I’m talking about the sim. I’ve seen no evidence that moving from the default 10km value, makes any difference in the HOJ pK.

In RL, when range info is unavailable via the onboard radar, the range information is input automatically either by the KMOD algorithm or Ground Automatic Control System. If range is unavailable through either of those options, only then is it input manually with info provided verbally by the Command Post (to paraphrase the manual).

Once the range is input, (again from the RL manual):
 

Quote

…the extent of the range scale is set to what would be appropriate for the number input and, then, changes automatically from that point onward (extrapolates)…

Among other things, there is no extrapolation in the sim. The range mark remains where you placed it.

Edit: And, out of curiosity, have any of you playing around with HOJ ever seen the “ПР” symbol appear (other than after burn through) like the quotation from the DCS manuals claims?

Edited February 9, 2022 by Ironhand

[okopanja]

1 hour ago, Ironhand said:

And, out of curiosity, have any of you playing around with HOJ ever seen the “ПР” symbol appear (other than after burn through) like the quotation from the DCS manuals claims?

Yes, in fact way before the aircraft is in range. Tried against F-15C

[Ironhand]

21 hours ago, okopanja said:

Yes, in fact way before the aircraft is in range. Tried against F-15C

Edit:

Without using launch override? I would love to see a short track of that, if you had the time. I’ve never seen it myself unless the radar had burned through the jamming.

Experimented a few minutes this morning. Got the “ПР” cue as long as I kept the input range at 25 km or less. In fact, the range marker actually moved a bit down the scale and back up depending on my airspeed (or so it seemed). Of course, during that time, the range to the target was much much farther.

Edited February 10, 2022 by Ironhand