MiG-21 cockpit illumination and new ASP

[foxbat155]

Hi all,

 

 

Lately I'm back to flying MiG-21, I did few night flights and I realize a few strange things in cockpit illumination:

 

 

 

I marked yellow, texts which should not have red highlight, in real cockpit those texts are made as a print with fluorescent paint.

Clock is a pure mechanical device and don't have any electrical connection with the aircraft and any battery inside. All scales and digits are painted with green fluorescent paint.

Autopilot control panel don't have any highlight at all, but should be red.

 

 

 

 

RL clock.

 

 

 

 

 

 

 

 

 

ARK rotary control switch should be fluorescent green.

 

 

 

 

Areas marked blue: they are red lights for highlighting instruments and small panels ( don't mistake with general flood lights), it's seems they not working or I'm wrong?.

Orange marked space: where is source of this light?, I'm asking because according manual should be there SK-1WM light.

 

 

 

 

 

 

 

Now gunsight's reflector. Compare to photos of RL device, first off all, lens reflection position is too low and is bigger like lens itself (green lines), and second this is size and position of fixed grid. According manual's drawings ( and logic because reflector glass is flat ) fixed grid reflection ( blue circle ) cannot be bigger like lens reflection ( red circle ), and moving grid cannot cross lens reflection borders.

 

 

 

[Frederf]

I think the uniform red "back light" is supposed to represent the red post lighting array without having to make dozens of individual light sources. It would be OK to have a non-uniform illumination mask but some of the gauge moving elements would look wrong because the illuminated spots would move with gauge animation. The flood lights are noticeably separate. Because of how it is implemented the post lights appear as back lighting.

 

Noted that reflective green paint is being colored red. I do not know if MiG-21 has UV flood which illuminates special reflective paint like Bf-109K-4.

 

White flood light is coming from a light fixture just below and at the forward edge of the emergency canopy release handle.

 

I would say the primary reason the HUD should be the same as the reflection of the emitter is because the light is columnated. The working area of the HUD and the reflection of the emitter should of course match. This suggests a dynamic reflection because eye point may change.

[Bogey Jammer]

About the lighting I found this: https://forums.eagle.ru/showpost.php?p=2819282&postcount=37 but it shows the red flood light, not the intrument post lighting (except a couple on the right console). Text backlight is emitting red.

 

About the reflector, hard to tell. Nothing prevent the optics to be tilted and to project a magnified image bigger than the main lens diameter.

 

But what buggers me now is the reflector's length in DCS way bigger than the real picture's. The curvature of the glass is different above the mounting brackets, and the proportions are not the same.

Edited July 23, 2018 by Bogey Jammer

[foxbat155]

I think the uniform red "back light" is supposed to represent the red post lighting array without having to make dozens of individual light sources. It would be OK to have a non-uniform illumination mask but some of the gauge moving elements would look wrong because the illuminated spots would move with gauge animation. The flood lights are noticeably separate. Because of how it is implemented the post lights appear as back lighting.

 

This is sim, all stuff the same like in reality, no simplifications, nobody said that sim developing is easy. Not "would be" but must be.

 

 

Noted that reflective green paint is being colored red. I do not know if MiG-21 has UV flood which illuminates special reflective paint like Bf-109K-4.

 

 

Those screens ( three first ) represent state without flood lights, yes you right with red flood lights on, fluorescent texts should be pinkish, but without flood lights should be green. Texts marked yellow works with illumination knob ( can be dimmer or lighter ) what is mistake.

 

 

About the lighting I found this: https://forums.eagle.ru/showpost.php?p=2819282&postcount=37 but it shows the red flood light, not the intrument post lighting (except a couple on the right console). Text backlight is emitting red.

 

About the reflector, hard to tell. Nothing prevent the optics to be tilted and to project a magnified image bigger than the main lens diameter.

 

But what buggers me now is the reflector's length in DCS way bigger than the real picture's. The curvature of the glass is different above the mounting brackets, and the proportions are not the same.

 

 

No, reflector cannot be tilted or moved from his position, need to be fixed at some constant values ( like distance from pilot's eyes, distance from gunsight's lens etc. ) because this guarantees proper aiming precision.

 

 

I have precise 3D model of ASP-PFD in 1:1 scale, so I did few quick renders:

 

 

View from pilot's point of view, 1,5 deg down and distance between pilot's eyes and reflector's surface about 700 mm.

 

 

10 deg. over normal view line.

 

 

10 deg. below normal view line.

 

 

Pilot's eye's level, 10 deg right from normal view line.

 

 

Those renders don't shows grid magnification by lens. Gunsight's lens have focal lenght 200 mm ( view angle 8,67 deg. ), distance beetwen reflector and lens is 77 mm, this means that grid reflection ( blue circle ) should be bigger about 7% like lens reflection ( red circle ).

 

 

 

[KilledAlive]

If this really is the case, no wonder why the Gunsight is so off when it comes to firing on Ground targets or other aircraft.

[BadHabit]

If this really is the case, no wonder why the Gunsight is so off when it comes to firing on Ground targets or other aircraft.

You mean deadly accurate, because off it is not.

[-Rudel-]

If this really is the case, no wonder why the Gunsight is so off when it comes to firing on Ground targets or other aircraft.

 

 

It is calibrated to work with the current grid.

[Frederf]

This is sim, all stuff the same like in reality, no simplifications, nobody said that sim developing is easy. Not "would be" but must be.

By easier I mean not to create but for our PCs to render. If each post light was independently rendered the developer could do it but our PCs couldn't. I don't know what tricks there are to render a complex light pattern on a dashboard with moving elements with their own variations in reflectivity.

 

Those screens ( three first ) represent state without flood lights, yes you right with red flood lights on, fluorescent texts should be pinkish, but without flood lights should be green. Texts marked yellow works with illumination knob ( can be dimmer or lighter ) what is mistake.

Yes I know post lighting knob should have very limited back lighting, mostly the right wall and right console have provision for illumination of text labels and switch from behind. Most everything else is front lighted from posts. Even primary flight gauges do not have integral lighting.

 

For columnated optics isn't focal length not related? Focal geometry takes parallel rays and focuses them at some distance (say 200mm) but it will also take rays diverging from a point 200mm away and turn them parallel. Thus the eye sees parallel rays as if they are coming from a very distant source. That's my understanding of it anyway.

 

So looking at contaminator output backward it should appear smaller (few %) than full HUD display because HUD display (in plane perpendicular to optical axis) is equal in size to lens size while viewing rays looking back at lens are divergent. I can explain like looking in an angled mirror at a 100mm disk. The disk will appear smaller the farther away. However if 100mm column image is projected then it will appear 100mm in size regardless of distance to disk. Of course optical path length from pilot's eye to lens disk is small so difference is minimal.

 

But for example reflection of columinating lens will be concentric and aligned with HUD image.

 

I will try some art mock up of what MiG-21bis cockpit might look like with proper post lighting.

 

Another image that probably replicates what things might look like: https://russianplanes.net/images/to169000/168979.jpg

 

1. Post lighting near instruments and placards

2. Some "built up" areas having rear illumination like right wall, weapon selection panel, right console

3. Red floods for general lighting4

4. Switches in back lighting area are not sealed so light falls on switches from behind

http://1.bp.blogspot.com/-VRFaAjsvuAk/TkPnuj712-I/AAAAAAAAAfM/72D6qj-Ytlc/s1600/IMG_2106.jpg

 

Later MiG-29 had integral lighting into gauges without posts but it was still from the front side https://combatace.com/uploads/post-61-1088628994.jpg I don't think MiG-21 has much of this at all.

 

Maybe white light for right wall panel is mounted inside cockpit beam that canopy jettison handle is on. This has some thickness and could have bulbs shining from inside the beam's bottom surface. Or dev removed it to avoid blocking pilot view.

Edited July 25, 2018 by Frederf

[Bogey Jammer]

Thus the eye sees parallel rays as if they are coming from a very distant source. That's my understanding of it anyway.

 

Mine too, the grid should be much more displaced and partially masked when viewing at an angle. Foxbat, if your model is accurate enough for optics, can you apply a refraction index for the lens ?

[KilledAlive]

It is calibrated to work with the current grid.

 

Pretty sure it's my own fault, but for some reason I am significantly more accurate using the Gunpods and the ASP gunsight set for the Pods. Using the standard cannon however, I have a lot of trouble picking off targets the size of HEMETTs, and I often use the static sight for that business.

[foxbat155]

Yes I know post lighting knob should have very limited back lighting, mostly the right wall and right console have provision for illumination of text labels and switch from behind. Most everything else is front lighted from posts. Even primary flight gauges do not have integral lighting.

 

 

Some gauges have own post lighting, eg KPP.

 

 

 

 

Here very good example how should look illumination (although photo is bit oversaturated):

 

 

-yellow circle for texts backlight,

-blue for instruments local lights,

-green for red flood lights,

-pink for white flood lights, here we have missed in Mig-21 lamp.

 

 

Second photo posted by you ( front MiG-23UB cockpit ) is great example how should look illumination with only local lamps and texts backlights.

 

 

 

For columnated optics isn't focal length not related? Focal geometry takes parallel rays and focuses them at some distance (say 200mm) but it will also take rays diverging from a point 200mm away and turn them parallel. Thus the eye sees parallel rays as if they are coming from a very distant source. That's my understanding of it anyway.

 

So looking at contaminator output backward it should appear smaller (few %) than full HUD display because HUD display (in plane perpendicular to optical axis) is equal in size to lens size while viewing rays looking back at lens are divergent. I can explain like looking in an angled mirror at a 100mm disk. The disk will appear smaller the farther away. However if 100mm column image is projected then it will appear 100mm in size regardless of distance to disk. Of course optical path length from pilot's eye to lens disk is small so difference is minimal.

 

 

 

Honestly, my knowledge about optics is really basic. But in my opinion focal lenght is related here. Diameter of fixed grid pattern (photo-etched plate) is about 1,5 smaller like lens, and probably that why lens have 200 mm, because grid picture need to be magnified. Here ASP-PFD optics schematics:

 

 

 

 

 

 

 

Mine too, the grid should be much more displaced and partially masked when viewing at an angle. Foxbat, if your model is accurate enough for optics, can you apply a refraction index for the lens ?

 

 

Unfortunately my CAD software is basic, no plugins for assigning optical properties to objects.

[foxbat155]

I found photo how should look type 75B cockpit lights without flood lights ( text and instruments lights ).

 

 

 

 

I took closer look on the radar CRT, and seems that only "Turn off" light is red, rest should be green ( or at least looks like green ).

 

 

[Bogey Jammer]

But… it's not the same display model :suspect:

[Toriy]

Hi all,

 

Clock is a pure mechanical device and don't have any electrical connection with the aircraft and any battery inside. All scales and digits are painted with green fluorescent paint.

 

There are 2 modifications - АЧС-1К (painted white for cockpits with red and white lights) АЧС-1Б (painted with green fluorescent). And АЧС-1МН has electric connection for internal red or white lightning. They also have an electric heater which automatically switches ON if the temperature drops below -5C and switches OFF if the temperature is more than 25C.

 

АЧС-1МН, Russian text, sorry.

http://www.measurement.ru/gk/vremya/03/07.htm

Edited August 13, 2018 by Toriy

[foxbat155]

But… it's not the same display model :suspect:

 

 

Nice try...., unfortunately CRT type is correct one:

 

 

 

 

On that photo lights are definitely red.

 

 

 

 

 

There are 2 modifications - АЧС-1К (painted white for cockpits with red and white lights) АЧС-1Б (painted with green fluorescent). And АЧС-1МН has electric connection for internal red or white lightning. They also have an electric heater which automatically switches ON if the temperature drops below -5C and switches OFF if the temperature is more than 25C.

 

АЧС-1МН, Russian text, sorry.

http://www.measurement.ru/gk/vremya/03/07.htm

 

 

MiG-21's have АЧС-1М, so no internal lights, only heating. When I wrote "no connection with aircraft" I meant "no connection with lighting system", my fault, I was not enough precise.

Edited August 13, 2018 by foxbat155

[Frederf]

It's a good picture of post lighting. It shows rather even light around affected areas but otherwise light/dark based on if zone has posts or not.

 

 

I'm not sure if that picture is only post lights however. I see flood type lighting cast onto weapon select panel and back lighting on for example RSBN control panel. Aren't these controlled by flood and console dials respectively?

[foxbat155]

It's a good picture of post lighting. It shows rather even light around affected areas but otherwise light/dark based on if zone has posts or not.

 

 

If you will look closer, is clearly visible source of those lights: all those small posts around instruments and panel. I think that picture in post procesing got lower contrast, that's why difference is small.

 

 

 

I'm not sure if that picture is only post lights however. I see flood type lighting cast onto weapon select panel and back lighting on for example RSBN control panel. Aren't these controlled by flood and console dials respectively?

 

 

No, no flood lights on this picture. IP have only two flood lights (yellow circle), right beside radar's control box:

 

 

 

 

On picture this place is completely dark and no visible cast from lights. Weapon panel is lighted (beside original post lights) by small light from device mounted on left side (red/blue circle). No idea what purpose have this thing, no information so far about.

 

 

 

 

RSBN panel have five backlight lights (APN), those are connected with backlight rheostat on the right side of cockpit.

 

 

 

 

Standard APN light used for backlight in many types of panel and control boxes in Soviet aircrafts.

 

 

 

Edited August 14, 2018 by foxbat155

[Toriy]

I never studied MiG-2bis but UM, so, sorry if I post wrongly. If I remember properly, there were 3 kids of lighting - 2 kinds of red and one white. White used only during entering the cockpit night time and to light the map during a flight. There were 2 white lamps - one on the left side, projecting to the right, and one on the right side, projecting to the left. Red lighting was Main and Emergency. Flood lights (4 lamps per cabin) are for Emergency lighting only, usually they are in Automatic mode and they start lighting when Main lighting is off or below some settings.

Edited August 14, 2018 by Toriy

[foxbat155]

Yes, two-seaters had more white flood lights: two per cabin. On combat variants was only one white light on the right cockpit side, and yes was used mostly only for maintance stuff, that's why in most aircraft was dissassembled and is realy hard to find photo of cockpit with this light.

I didn't know that red flood is emergency only, do you have any info about this from manual?.

[Frederf]

If you will look closer, is clearly visible source of those lights: all those small posts around instruments and panel. I think that picture in post processing got lower contrast, that's why difference is small.

Yes I see. I was commenting how even the post lighting is (at least in photo) despite being obviously from posts.

 

 

No, no flood lights on this picture. IP have only two flood lights (yellow circle)

I am reading other MiG-21bis manual which shows additionally red fixtures SM-1KM on each side of cockpit, four total. The white fixture is SM-1бM. I think "K" is for красный (red) while "б" is for белый (white).

 

 

I'm not sure which fixtures are tied to rheostat "instrument board" and which to rheostat "console" knobs. Maybe it is just as easy as center panel and side panels? I would think that helpful duty is for one knob for "flight critical" instruments and one knob for everything else. Para. 105(d) isn't clear.

 

 

 

Interestingly Para. 103 of same manual does use English words "main" and "emergency" for lighting systems. It uses the word "main" to refer to the system other than the floods. Maybe it thinks of floods as "emergency"? It assures pilot that main or emergency alone may be sufficient but best is a combination.

 

 

 

On picture this place is completely dark and no visible cast from lights. Weapon panel is lighted (beside original post lights) by small light from device mounted on left side (red/blue circle). No idea what purpose have this thing, no information so far about.

 

 

It looks like some extra piece which will have a box mounted to it by four threaded holes. I guess it can be ignored as it's not in DCS airplane. Not sure why they chose to use 360 cylinder light in this way either.

 

 

 

RSBN panel have five backlight lights (APN), those are connected with backlight rheostat on the right side of cockpit.

 

 

Ah yes, funny "bolts". With these it can be easy to see where "sunken post" (APN) lights are and which items have illumination from behind and which not. There are many of them

 

 

I do see unusual items on console, example aft of three oxygen system switches. Is this a "mushroom" style light to provide illumination? So this would be part of consoles dial and not instruments even though it is a post? Are instrument and console rheostat each of mixed lights? (type CB or C, APN).

 

 

And lastly if we fully understand what lighting should look like... is it practical to illuminate DCS module in this way? If it is modeled as so many individual light sources it will take a super computer to display. Are there tricks to make "splotchy" light render without individual light sources?

[Bogey Jammer]

Light is pre-rendered and baked into textures I think.

[Frederf]

Currently, probably. But that's now where all the instruments are magically internally backlit perfectly evenly so you don't notice when stuff animates.

 

 

If it was changed to look like post lighting the splotches would animate and drag their light splotches around with the gauge animations in a weird way.

[Toriy]

...

I didn't know that red flood is emergency only, do you have any info about this from manual?.

Oh, sorry, my mistake. There is a Note in the Manual which recommends to use main and flood lights together to avoid glare lights on the canopy.

At the same time the manual , page 106 (chapter "Система внутрикабинного освещения") describing the emergency lighting mentions flood lights. This was the source for my mistake.

[foxbat155]

Thanks Toriy, I found this in my MiG-21UM manual.

 

 

 

 

 

I am reading other MiG-21bis manual which shows additionally red fixtures SM-1KM on each side of cockpit, four total. The white fixture is SM-1бM. I think "K" is for красный (red) while "б" is for белый (white).

 

 

Yes aircraft have four red lights in total ( two on the IP, one left cockpit side, one right cockpit side ), and one white light which is use mostly only by ground service during night servicing and generally is disassembled from cockpit ( probably that's why LNS did white light without visible fixture ).

 

 

I'm not sure which fixtures are tied to rheostat "instrument board" and which to rheostat "console" knobs. Maybe it is just as easy as center panel and side panels? I would think that helpful duty is for one knob for "flight critical" instruments and one knob for everything else. Para. 105(d) isn't clear.

 

 

All APN's with "console" knob, all S-60, S-80, SW, AGL with "instruments" knob, there is no distinction for left console, right console or instrument panel, all lights groups are activated by one dedicated knob in the same time.

 

 

Interestingly Para. 103 of same manual does use English words "main" and "emergency" for lighting systems. It uses the word "main" to refer to the system other than the floods. Maybe it thinks of floods as "emergency"? It assures pilot that main or emergency alone may be sufficient but best is a combination.

 

 

Yes this is thing pointed by Toriy, in two-seaters aircrafts flood light have additional switch "Manual-Auto". In manual mode flood light are operated by pilot by knob, in automatic mode ( and seems this default situation ) flood lights are emergency lights: if "instruments" lights electric installation will fail, then automatically red flood lights are on. I was looking in cockpit for this switch but no succes, maybe is hidden in one of service panels outside cockpit, but if manual mention about this, probably flood lights funcionality is the same like in two-seaters.

 

 

I do see unusual items on console, example aft of three oxygen system switches. Is this a "mushroom" style light to provide illumination? So this would be part of consoles dial and not instruments even though it is a post?

 

 

This is SW light, part of "instruments" lighting.

 

 

And lastly if we fully understand what lighting should look like... is it practical to illuminate DCS module in this way? If it is modeled as so many individual light sources it will take a super computer to display. Are there tricks to make "splotchy" light render without individual light sources?

 

 

Yes, definitelly this is no easy to do, here IP example:

 

 

 

 

Red circle - APN's lights, yellow - S-60, blue - S-80, pink - AGL, orange SW. But we have to remember that is no light simulation in cockpit, only textures. Already we have three groups of lights, they need only modification.

[Toriy]

Like

There are some other videos with a bit different colourisation.