reported Mi-8 DISS-15 Doppler nav rollercounter detail

[TasDozer]

I've spotted some rather niche issues with the DISS-15 Doppler navigation controller which might be satisfying to fix!

The Lateral Deviation (БОКОВОЕ УКЛОНЕНИЕ КМ) and Distance (ПУТЬ КМ) displays are each dual roller-counter displays:

(OK, separately, in the English cockpit mod the labels are all misleading. They should be "LATERAL DEVIATION KM", "DISTANCE KM", and "COURSE ANGLE".)

The Lateral Deviation display looks like this when you're off course to the left:

And it looks like this when off course to the right:

However - the word "RIGHT" should appear on the other side, like this:

The display actually has six drums - three for "negative" (left-error) deviation and three for "positive" (right-error) deviation. "LEFT" and "RIGHT" are written a shutter that moves to hide the inapplicable drums as the aircraft passes 0KM deviation.

Exactly the same applies to the "Flight Path KM" / Distance KM / ПУТЬ КМ display and the "FORWARD" and "AFT" shutters.

You can see this kind of mechanism in this video at 13:00 - this is also a Doppler navigation control unit but I don't the guy knows this:

Note the "negative"/left/aft drums have the digits in the opposite order:

If you're wondering if I am a little bit obsessed with these roller-counters and with Doppler navigation instruments... you're absolutely right! I have a Doppler navigation computer in my living room, to a 1950s design - a generation older when it came to these roller-counter displays but the same general principle - two sets of drums and a shutter:

I made a working 3D model and simulation of this Doppler system and computer for X-Plane 10 back in the day. (I should complete that project.)

One other facet: I am 90% certain that, if you hold down the "Left", "Right", "Fwd", or "Aft" buttons, the motion should stop automatically on reaching 0 KM, and resume if you press the button again, based on the manuals for similar but older equipment in other aircraft. So, if you reach a waypoint showing 1.2 KM deviation to the right of track, if you press and hold "Left", and move your attention elsewhere, when you look back at the DISS-15 you'll see deviation steady at 0KM. Pressing "Left" again would resume the motion of the digits and show an increasing deviation to the left of track.

Benefits of simulating this display:
- clearer if you're left/right of track or before/after the waypoint based on a glance at which shutter is visible
- indicates to the user how these amazing mechanisms worked
- just looks cool

I love using the DISS-15, by the way. I've got its controls bound to HOTAS shortcuts, I use it that much. And I really appreciate the correct animation when a digit changes from 9 to 0 and drags the next drum along with it, e.g. when 39 changes to 40. So many sims get this wrong.

Edited March 8, 2023 by TasDozer

[Devrim]

Let me investigate the EN label side for my mod and ED's cockpit files. Thank you for your research.

[BuzzLine]

21 hours ago, TasDozer said:

If you're wondering if I am a little bit obsessed with these roller-counters and with Doppler navigation instruments... you're absolutely right!

An elegant weapon display system, for a more civilized age.  

I love learning how stuff works. Thank you for sharing !

[Flappie]

Thank you @TasDozer.

An internal request has been made to fix this inaccuracy for both Mi-24 and Mi-8 modules.

[TasDozer]

Thanks folks

[gulredrel]

Thanks a lot for sharing. Never thought of that. An amazing electromechanical piece of kit. Hope this can be implemented in Mi-8 and -24.

[DeMonteur]

On 3/8/2023 at 3:55 AM, TasDozer said:

One other facet: I am 90% certain that, if you hold down the "Left", "Right", "Fwd", or "Aft" buttons, the motion should stop automatically on reaching 0 KM, and resume if you press the button again, based on the manuals for similar but older equipment in other aircraft. So, if you reach a waypoint showing 1.2 KM deviation to the right of track, if you press and hold "Left", and move your attention elsewhere, when you look back at the DISS-15 you'll see deviation steady at 0KM. Pressing "Left" again would resume the motion of the digits and show an increasing deviation to the left of track.

DISS-15  counters don't stop on 0 deviations. It just continues up to 999km where it suppose to stop( I've never tested it because it took pretty long to get there).

Moreover the heading counter drum goes roughly frrom 995 to 365 degrees.

I hope you will have DISS-15 in almost all its crappiness soon  

 

Edited July 29, 2023 by DeMonteur

[PawlaczGMD]

Slightly off-topic, the English cockpit contains a few more bad/mis-translations. It could stand to be updated.

[Flappie]

5 hours ago, PawlaczGMD said:

Slightly off-topic, the English cockpit contains a few more bad/mis-translations. It could stand to be updated.

Please open a new thread (it's free of charge) and list the errors you found. I'll report them to devs.

[PawlaczGMD]

4 hours ago, Flappie said:

Please open a new thread (it's free of charge) and list the errors you found. I'll report them to devs.

I'm not a Russian speaker, so I'm not the best person to do this and find them all. But you can see an example here, all 3 labels in a single instrument are inaccurate or straight up misleading.

[Flappie]

On 2/18/2024 at 9:00 PM, PawlaczGMD said:

I'm not a Russian speaker, so I'm not the best person to do this and find them all. But you can see an example here, all 3 labels in a single instrument are inaccurate or straight up misleading.

I'll report these. In the English manual, they are indeed explicitly called "COURSE ANGLE", "LATERAL DEVIATION" and "DISTANCE".

They are properly translated in the Mi-24P.

[TasDozer]

There's a fun way to use the DISS-15 as an area navigation tool. Set COURSE ANGLE to the magnetic heading of the vertical axis of the local MGRS grid. Set LATERAL DEVIATION to your east-position and DISTANCE to your north-position.

So if your position is JJ2460, you'd set 024km Right and 060km Forward and turn on the DISS-15. As you fly around your east-west(ish) movement affects Lateral Deviation and north-south(ish) affects Distance. If it's now showing 033 Right and 084 Forward, you're in JJ38, JJ3384 to be precise. If it's 133 Right you've flown out the east side of JJ and are in the next 100km square, KJ. If it's 184 Forward you've gone north into JK. (you need to reference yourself to a 100km square you're not going to go south or west of for this to work.)

I made a video last year demonstrating this but I'd like to redo it using slides and video-editing for clarity, rather than doing it in one take... is there a possibility the textures will be patched within, say, months? If so I'll wait for the update before doing this!