Some things I learned from the real AJS37 manual

[LastRifleRound]

After much study and some hilariously bad translations (trigger unsafe=unsecurity, designate=uncertainty, dropping as in precision drop=precipitation to name a few), I had occasion to thoroughly read the flight manuals posted graciously on this forum.

 

I learned a lot that I didn't already know, and it brought up some questions as well. This comes from part 2 of the manual. Page numbers (the .pdf page numbers, actual pages are missing from the document so they don't line up) are listed to support the insight.

 

pg10

The WP circle (referred to in the manual as the PPI) is docked to the edge of the radar scope in the direction you'd find it when it is out of view

 

pg15

When RB04 is selected and mode ANF, the center vertical line in the CI is actually canted to account for wind (so it isn't straight up and down in the presence of crossing winds). Laying the center line on the target will adjust for wind. Not sure if this is modeled in our version

pg18

The Bscope with RB04 also shows the wind-corrected vertical line, as well as the horizontal ranging lines if one of them happens to be in view. Not sure if modeled.

pg17

A2 mode is designed to show an area +/- 20 degrees to either side of the PPI with a distance of +3.5km and -6.5km up and down from the center of the PPI. The view is stabilized there until you get close enough to the bottom edge when it starts to "snowplow". How close this is is dependent on your current distance setting as follows:

1. range setting 15: display snowplows when aircraft .6km from the bottom edge of the scan

zone

2. range setting 30: 1.2km away

3. range setting 60: 2.4km away

4. range setting 120: 4.8km away

pg58

The vertical line in RR bombing mode is also wind-corrected like the RB04. Unsure if modeled.

pg59

The HUD should guide to the safety altitude in RR mode with trigger unsafe. Not sure if it does.

 

The next few pertain to PLAN mode:

pg55

This one is a little confusing. This page talks about PLAN mode. The 6 prior pages are missing, but the page starts off saying "Osakring(3) should not occur at a distance greater than 4000m if the attack is carried out from a height that is less than the safety distance" I'm not sure what this means. I wonder if it has something to do with the pre-designation guidance? I can't seem to get a good translation on the word "Osakring", coming up with something similar to "fuse" or "cocking (like making a firearm/bomb ready)" in English.

pg55

If you pull the trigger before the wings flash, the bombing solution will be less accurate

pg55

When the wings flash, you have .5s to pull the trigger. Anywhere in that .5s will yield the same results. If you are late, the bombing system will make up for it by clustering the first few munitions as necessary closer together until it can release the rest at the right spacing.

pg55

The actual designation for the bombing solution is at trigger press, not trigger unsafe. Trigger unsafe designates the target for height and lateral guidance, but the final solution is determined by the cursor position when you pull the trigger. This is where the target fix is placed as well.

pg55

The steering order should be followed even after FALLD LAST, as it it is timed to turn off after the last bomb has IMPACTED, not RELEASED. Presumably this is to ensure you don't dip below the safety altitude.

 

The next insights have to do with DYK:

pg54

-Ideally you will have 3.5s of 'dot on target' before release to get the most precise firing solution

-The trigger should NOT be pressed before wings lit. Though possible, the solution will be degraded.

-Again, where the dot is when the trigger is pressed is the spot you are telling the bombing computer you want to hit.

-Nowhere in this particular manual does it say it factors in a 4g pull to have proper bomb spacing. The way it reads, you should achieve proper spacing even if you do not pull up at all.

-The steering order is not a 4g pull up cue per se. It is the position your dot should be at or above 2.4s after release has commenced, and is based on your safety altitude. The higher the altitude, the earlier you need to release before dipping below. 2.4s after release has begun your targeting dot should be at or higher than the SO. The SO is ALWAYS supposed to be above the targeting dot while diving. It does NOT have anything to do with your G being pulled or enforcing proper bomb spacing.

-The manual shows the Viggen pulling up to an altitude of only 800m on this maneuver, so you are meant to pop up much closer to the target than is typical and your dive angle is meant to be shallower than what I'm used to

 

I have a lot more testing to do! I'm going to test out the DYK mode to see if I can perfect the delivery, and see if wind correction is currently active for RR and RB04 modes, as well as the Bscope mode for RB04.

 

Interestingly the manual does not say anything about radar fixing in A2, so I think it was right to pull that. I guess it could be a feature of the real jet but it would be odd for the manual to not mention it at all if it was.

 

Hope others find this useful

Edited February 27, 2020 by LastRifleRound

[TOViper]

Sure I indeed find your posting very interesting, and thanks for sharing your experiences! I find it super interesting how deep we are digging into it :)

[Holton181]

Osäkring (i presume it's an 'ä' and not an 'a') in this context:

O- = Un-

säkring = safe

Osäkring = unsafe

[Snappy]

Where did you the real AJS37 manual from?

 

Edit: Disregard ,feeling somewhat stupid ;)

 

Regards,

 

Snappy

[hilmerby]

There seems to some confusion here. IRL we fired at "wing out" used 4G for the pull up and followed the small cirkle "SO". As soon as we got "Fälld Last" (Bombs gone) we could start our turn down to low level again. The bombs left the Aircraft later during the "pull up", in DCS they seems to fall much sooner. We flew towards the Target, at distance 10km made a turn to the left or right 10 degree, pull up just below distance to target 6 km, climb with 20 degree, roll at 300m. This is not really possible in DCS. I have modified the procedure. Turn at 15 km, pull up at 7 and roll at 450.

I have started to put some videos on Youtube, describing the Viggen procedures. So far only in Swedish. This is a divebomb attack

[randomTOTEN]

Yes there is a lot of confusion hilmerby,

 

 

Same procedure for BOMB PLAN (Level Release)? 4G Pull to follow SO?

[LastRifleRound]

There seems to some confusion here. IRL we fired at "wing out" used 4G for the pull up and followed the small cirkle "SO". As soon as we got "Fälld Last" (Bombs gone) we could start our turn down to low level again. The bombs left the Aircraft later during the "pull up", in DCS they seems to fall much sooner. We flew towards the Target, at distance 10km made a turn to the left or right 10 degree, pull up just below distance to target 6 km, climb with 20 degree, roll at 300m. This is not really possible in DCS. I have modified the procedure. Turn at 15 km, pull up at 7 and roll at 450.

I have started to put some videos on Youtube, describing the Viggen procedures. So far only in Swedish. This is a divebomb attack

 

Thank you for posting this. Having feedback from a Viggen pilot is invaluable. Looks like the pull is even lower than what I was doing.

 

I will say before the update that made bombs fall short, bombs in dyk would drop later than they do now. Maybe after the next update we can give the 300m at 6km profile another shot.

 

Can you do one on PLAN?

[LastRifleRound]

There seems to some confusion here. IRL we fired at "wing out" used 4G for the pull up and followed the small cirkle "SO". As soon as we got "Fälld Last" (Bombs gone) we could start our turn down to low level again. The bombs left the Aircraft later during the "pull up", in DCS they seems to fall much sooner. We flew towards the Target, at distance 10km made a turn to the left or right 10 degree, pull up just below distance to target 6 km, climb with 20 degree, roll at 300m. This is not really possible in DCS. I have modified the procedure. Turn at 15 km, pull up at 7 and roll at 450.

I have started to put some videos on Youtube, describing the Viggen procedures. So far only in Swedish. This is a divebomb attack

 

Ok I tried a few runs after the latest update. I just can't get the same results you do. Also, the SO looks like it's all over the place and I don't really know what it's doing. If you stay in the exact same dive angle, it moves straight down to the bottom of the hud without me having to pull up at all. This seems like the opposite of intended behavior. I also can't get a good string of bomb length. They're either too compact from not pulling or too long from pulling. The last run I nail a perfect 4g pull and it still doesn't get the right spread. It almost seems like the bombing computer in DYK is releasing right away at some arbitrary point of "wing out" regardless of parameters, so the the reticule position after trigger pull when wings out isn't the one used, it's wherever the reticule is about .5s after wing out is the actual target position, meaning you can't possibly pull up and target with any precision, you need to pick one or the other.

 

Here's a few runs I tried using your methodology. Let me know what you see here. (and, of course, if I did anything wrong.)

 

 

EDIT: Did several more runs. I'm starting to think DYK in DCS is way too quick to drop bombs. Often it will drop the whole stick in one shot right at wing out. According to the flight manual this just shouldn't be happening. Would be good if some of you other OB guys would test this, too.

Edited March 8, 2020 by LastRifleRound

[Wintermute74]

Your YouTube video is empty LastRifleRound, mind try uploading it again?

[LastRifleRound]

Sorry About that, proper link is here:

 

[LastRifleRound]

I think I figured out what's going on here. DYK looks to be releasing bombs with the aimpoint as the beginning of the string rather than the middle. If others could try this out and tell me what they see that'd be great.

[amalahama]

I think I figured out what's going on here. DYK looks to be releasing bombs with the aimpoint as the beginning of the string rather than the middle. If others could try this out and tell me what they see that'd be great.

 

I think that's the intended behaviour. I remember having seen one post discussing this

[QuiGon]

Sure I indeed find your posting very interesting, and thanks for sharing your experiences! I find it super interesting how deep we are digging into it :)

I concur! :thumbup:

 

There seems to some confusion here. IRL we fired at "wing out" used 4G for the pull up and followed the small cirkle "SO". As soon as we got "Fälld Last" (Bombs gone) we could start our turn down to low level again. The bombs left the Aircraft later during the "pull up", in DCS they seems to fall much sooner. We flew towards the Target, at distance 10km made a turn to the left or right 10 degree, pull up just below distance to target 6 km, climb with 20 degree, roll at 300m. This is not really possible in DCS. I have modified the procedure. Turn at 15 km, pull up at 7 and roll at 450.

I have started to put some videos on Youtube, describing the Viggen procedures. So far only in Swedish. This is a divebomb attack

Very interesting! Unfortunately I don't speak Swedish to be able to really enjoy your videos :(

[amalahama]

@RagnarDa, any comments on adding any of the RL functionalities raised by the OP? I'd like to see the wind-corrected RB04 and RR lines and the changes in DYK and PLAN modes.