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Central Indicator (CI/radar) 100 m reference line doesn't move as altitude changes


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I was flying with the altitude mode in RHM (radar altimeter) and the radar in Terrain Avoidance mode, and looking at the Central Indicator (CI, the radar display) representation of the horizon reference line, pole track, and 100 m reference line to try to use them for head-down low altitude flying.  I noticed when I hit the Reference button, the 100 m reference line on the CI updates its vertical position, but it then remains fixed there and doesn't move if the aircraft changes altitude.  The CI pole track does move up and down as the radar altitude changes.

 

I don't have the ability to take a screenshot or track at the moment, so I'm first wondering if anyone else has noticed this.  I couldn't find a post about it using the forum search, but I don't know if I used the right search terms.

"Subsonic is below Mach 1, supersonic is up to Mach 5. Above Mach 5 is hypersonic. And reentry from space, well, that's like Mach a lot."

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I'm referring to these symbols on the CI display.  This figure is from page 109 of the Viggen manual.  As far as I can tell, the 100 m line doesn't change length at all except when the Reference button is depressed.

 

image.png

"Subsonic is below Mach 1, supersonic is up to Mach 5. Above Mach 5 is hypersonic. And reentry from space, well, that's like Mach a lot."

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I think is normal, when you set the reference (set) altitude, you have a visual indication of you position between this reference, and the reference bar (100m) as the name say is a reference of 100m and it help you for visualy scaling the set altitude.

[sIGPIC][/sIGPIC]

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20 hours ago, JG300_Papaye said:

I think is normal, when you set the reference (set) altitude, you have a visual indication of you position between this reference, and the reference bar (100m) as the name say is a reference of 100m and it help you for visualy scaling the set altitude.

It's the same symbol as on the HUD.  I have a hard time believing it's not intended to move.  A static 100m line is not a 100m line.

"Subsonic is below Mach 1, supersonic is up to Mach 5. Above Mach 5 is hypersonic. And reentry from space, well, that's like Mach a lot."

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The same schematics is found page 269 of the real SFI AJS37 del kap 1 SFI manual , but there are no explanations. Here's the CI presentation, page 267:

 

Centralindikatorn har som huvuduppgift att presentera information från flygplanets radar i form av sektor - PPI, alternativt som B-skopspresentation. Radarbilden presenteras på indikatorns bildrörsenhet i form av svart video, vilket ger en bild med mörka radarekon i varierande gråtoner. Se Bild 8.
PPl-presentationen ges i ett polärt koordinatsystem (vinkel- och avståndsriktig presentation), medan B-skopspresentationen utgörs av ett rätvinkligt koordinatsystem med vinkelangivelse i x-led och avstämd i y-led. B-skopspresentationen blir något förvrängd i jämförelse med PPIbilden (alltmer expanderad närmare det egna flygplanet). En del av centralindikatorn utgörs av en kursindikator, som är placerad så att den omger indikatorns bildrörsenhet. Kursindikatorn visar bl a flygplanets aktuella kurs. Se närmare Flik 20 Flyglägesinstrument FLI 37.

 

The main indicator's main task is to present information from the aircraft's radar in the form of sector - PPI, alternatively as a B-scope presentation. The radar image is presented on the indicator's picture tube unit in the form of black video, which gives an image with dark radar echoes in varying shades of gray. See Figure 8. The PP1 presentation is given in a polar coordinate system (angular and distance-correct presentation), while the B-scope presentation consists of a right-angled coordinate system with angular indication in the x-direction and tuned in the y-direction. The B-scope presentation is slightly distorted in comparison with the PPI image (increasingly expanded closer to the own aircraft). Part of the central indicator consists of a course indicator, which is positioned so that it surrounds the indicator's picture tube unit. The course indicator shows, among other things, the aircraft's current course. Take a closer look at Tab 20 Flight mode instrument FLI 37.

 

Then, the manual deals with the HUD indications. Not much is said about the CI 100m reference.

 

But I agreee with you, @Machalot: I can't see how this could be a "100m reference" if it was static.

 

EDIT: I keep searching in the other manuals.


Edited by Flappie

A track or it didn't happen.

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6 hours ago, Machalot said:

It's the same symbol as on the HUD.  I have a hard time believing it's not intended to move.  A static 100m line is not a 100m line.

Understood the same thing than you, I misunderstood your first issue

[sIGPIC][/sIGPIC]

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12 hours ago, Flappie said:

The same schematics is found page 269 of the real SFI AJS37 del kap 1 SFI manual , but there are no explanations. Here's the CI presentation, page 267:

 

Centralindikatorn har som huvuduppgift att presentera information från flygplanets radar i form av sektor - PPI, alternativt som B-skopspresentation. Radarbilden presenteras på indikatorns bildrörsenhet i form av svart video, vilket ger en bild med mörka radarekon i varierande gråtoner. Se Bild 8.
PPl-presentationen ges i ett polärt koordinatsystem (vinkel- och avståndsriktig presentation), medan B-skopspresentationen utgörs av ett rätvinkligt koordinatsystem med vinkelangivelse i x-led och avstämd i y-led. B-skopspresentationen blir något förvrängd i jämförelse med PPIbilden (alltmer expanderad närmare det egna flygplanet). En del av centralindikatorn utgörs av en kursindikator, som är placerad så att den omger indikatorns bildrörsenhet. Kursindikatorn visar bl a flygplanets aktuella kurs. Se närmare Flik 20 Flyglägesinstrument FLI 37.

 

The main indicator's main task is to present information from the aircraft's radar in the form of sector - PPI, alternatively as a B-scope presentation. The radar image is presented on the indicator's picture tube unit in the form of black video, which gives an image with dark radar echoes in varying shades of gray. See Figure 8. The PP1 presentation is given in a polar coordinate system (angular and distance-correct presentation), while the B-scope presentation consists of a right-angled coordinate system with angular indication in the x-direction and tuned in the y-direction. The B-scope presentation is slightly distorted in comparison with the PPI image (increasingly expanded closer to the own aircraft). Part of the central indicator consists of a course indicator, which is positioned so that it surrounds the indicator's picture tube unit. The course indicator shows, among other things, the aircraft's current course. Take a closer look at Tab 20 Flight mode instrument FLI 37.

 

Then, the manual deals with the HUD indications. Not much is said about the CI 100m reference.

 

But I agreee with you, @Machalot: I can't see how this could be a "100m reference" if it was static.

 

EDIT: I keep searching in the other manuals.

 

Maybe there's something in the section about Terrain Avoidance mode?

"Subsonic is below Mach 1, supersonic is up to Mach 5. Above Mach 5 is hypersonic. And reentry from space, well, that's like Mach a lot."

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  • 5 months later...

@IronMike Not sure if you ever saw this one back in the day.  It was not acknowledged at the time.

"Subsonic is below Mach 1, supersonic is up to Mach 5. Above Mach 5 is hypersonic. And reentry from space, well, that's like Mach a lot."

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