Heading correction dial ("KURSKORR") not working

[TOViper]

OB 2.8.0.33006
SP
Syria

The heading correction dial ("KURSKORR") - on the right side panel - seems not to have any effect. See attached TRK.
What should happen IMHO is that when changing the magnetic variation with the "heading correction dial", the CI (and the ADI) should change.
For this mission, for that date, the magnetic variation at that location in Syria is +10°.

I am pretty sure that the knob - in the past - changed something, but IIRC it changed the standby compass heading (which would be totally wrong), instead of the values on the CI and the ADI. What I currently cannot figure out is if the knob must be changed on ground (e.g. in mode BER), or if it can be changed in flight as well.

 

2022-11-27_AJS37_KURSKORR_failes.trk

[Machalot]

2 hours ago, TOViper said:

OB 2.8.0.33006
SP
Syria

The heading correction dial ("KURSKORR") - on the right side panel - seems not to have any effect. See attached TRK.
What should happen IMHO is that when changing the magnetic variation with the "heading correction dial", the CI (and the ADI) should change.
For this mission, for that date, the magnetic variation at that location in Syria is +10°.

I am pretty sure that the knob - in the past - changed something, but IIRC it changed the standby compass heading (which would be totally wrong), instead of the values on the CI and the ADI. What I currently cannot figure out is if the knob must be changed on ground (e.g. in mode BER), or if it can be changed in flight as well.

 

2022-11-27_AJS37_KURSKORR_failes.trk 127.71 kB · 1 download

Last I checked, you can see the effect of this knob by setting it to the wrong value and then aligning with the runway and pressing the Reference button. The CI will slowly rotate until it shows the runway heading, offset by the magvar error.  Not sure if this is correct behavior but it does have this effect. 

[TOViper]

Last I checked (today): This doesn't work. The dial simply has no effect currently.

[Machalot]

7 hours ago, TOViper said:

Last I checked (today): This doesn't work. The dial simply has no effect currently.

Confirmed.  I will put in a bug report.

[Arink429]

Hi, any new about this? I'am a new Viggen driver and I noticed that the headings shown on CI and ADI are not corrected by KURSKORR movement. The dial action turns the back up compass only.
Example: Nevada: Runway 03, magnetic heading 029, the CI shows 04  (+11 deg mag var.) KURSKORR changes the compass readings only.

[Zabuzard]

Not a Viggen expert, but afaik this is correct behavior.

Only the magnetic compass is influenced by the magnetic heading setting.
The other compass is a gyrocompass, initialized on the runway takeoff heading that you entered.
The magnetic compass is only used as backup system and during takeoff as fallback, in case it differs too much from the entered runway heading.

The Viggen just assumes that, when you takeoff, the current heading is the entered runway heading (and the coordinates of the runway center as takeoff reference location). Take that as reference and compute the current position and heading based on the movement after takeoff only. So the magnetic compass plays no role at that point anymore.

The main reason why everything in the Viggen uses true and not magnetic heading is because the magnetic heading changes a lot around Sweden. So the Viggen pilots would otherwise have to constantly correct the heading setting midflight during a sortie. Kinda annoying. So instead, you just have to make sure that you takeoff at the entered heading (or hit the reference button at takeoff) and you are good to go.