Russian AC Navigation

[504Goon]

Does someone know how does the real russian navigation system work? How much is pre programmed to the aircraft computer, where does the HSI get all the info.. GPS cannot be the option, and wouldn't radio beacons also be a bit out of place during war?

[169th_Viking]

Inertial?

 

IRS.

[23rd_Drago]

Not an expert, but I think it’s done very simple by uploading map coordinates and elevation into flight computer. By knowing exact coordinate of the aircraft prior to takeoff, computer calculates speed, angle, direction and how much time the aircraft has traveled… thus giving you constant location of the aircraft. Again, don’t quote me on this… I’ve either made this up or read about it long time ago…

[Olgerd]

MiG-29 navigation system has the following operation modes:

1) autonomous inertial (only with fully aligned gyros). Uses accelerometers for velocity components calculation;

2) autonomous with air data system support (much more erratic);

3) same as first but also with RSBN (ground beacons nav system similar to VOR+NDB) support. It is one with the best presicion;

4) same as second but with RSBN support.

[yamangman]

1) autonomous inertial (only with fully aligned gyros). Uses accelerometers for velocity components calculation;

 

Do you know how accurate this is? Can you estimate the degree of innacuracy there is a model it in your next flight sim?

[Olgerd]

About 8 km per one flight hour. Many depends on avaliability of information for particular plane. I think it is possible to model such things.

[504Goon]

Thanks, just what i wanted to know:)

[britgliderpilot]

About 8 km per one flight hour. Many depends on avaliability of information for particular plane. I think it is possible to model such things.

 

That sounds right - according to my lecturers, even the best Inertial Nav Systems can only manage 3-4nm per hour. Nav beacons for approach, of course.

 

 

Out of interest, how much information do you guys have about the navigation modes on the Su27 HDD?

 

I understand the MiG29 HDD isn't supposed to display any Nav information . . . . is there any intention to model this in future?

[Olgerd]

The scanned version of Su-27SK (Chinese version, but completely copies many systems from Russian variant) flight manual is in public access now. It is in russian. It has very usefull description of Su-27 HDD indication in TACT mode.

Right now we are working on Ka-50... ;)

[SUBS17]

Hey Olgred, in Falcon 4 the F-16s INS takes 8 minutes to warm up so the aircraft takes about 12 minutes for a complete ramp start. Does the Su27 and Mig 29 take this long for the INS to align and if it does would that be implemented in the lockon successor if you guys put one in?

[169th_Cobra]

That sounds right - according to my lecturers, even the best Inertial Nav Systems can only manage 3-4nm per hour. Nav beacons for approach, of course.

 

not sure if you are talking about fighter systems but on the 747-400 i have seen an error of only 2-3nm flying from Syd-Lax with only 2 decent updates (the last around Nadi and we were too far south of Hawaii to get on from there before hitting the west coast.) pretty impressive if you ask me.

 

here is a photo of the navigation data i took on a 737-800 just this week as the same topic came up on our own boards.

 

-aircraft position is the tip of the triangle

-gps position is the tie-fighter symbol (circle with little arms on it) which is right on the aircraft position

-the irs positions (2 of them) are the star's * just to above and left of the aircraft position.

-u can see the map scale by the 2.5nm marker half way up (measured from the tip of the triangle)

-photo taken about 40mins into a 1:20 sector

 

 

:)

[britgliderpilot]

The scanned version of Su-27SK (Chinese version, but completely copies many systems from Russian variant) flight manual is in public access now. It is in russian. It has very usefull description of Su-27 HDD indication in TACT mode.

Right now we are working on Ka-50... ;)

 

Ah, so that's "We know, but have other things to work on at the moment".

 

Fair enough, I suppose :)

[Olgerd]

Ah, so that's "We know, but have other things to work on at the moment".

 

Fair enough, I suppose :)

 

Yes. :icon_wink

[Olgerd]

Hey Olgred, in Falcon 4 the F-16s INS takes 8 minutes to warm up so the aircraft takes about 12 minutes for a complete ramp start. Does the Su27 and Mig 29 take this long for the INS to align and if it does would that be implemented in the lockon successor if you guys put one in?

 

Mig-29 and Su-27 have two nav system "readiness modes" - normal and fast.

In "normal" mode you have to wait about such time, and you will get fully aligned gyros. "Fast" mode will be switched on if you will stop aligning in 1.5 minutes after start. In this mode you will get only partially aligned gyros and the system will work in "autonomous with air data system support" mode.

[SUBS17]

Thanks for that Olgred, I always wondered how long it took for a

russian aircraft to ramp up.

cheers

Subs