Odd Occurrence-- What Happened to the Sun?

[b3burner]

Don't know if this just started happening, or it's been happening awhile and I just noticed it last night.

I have an issue where if I fire up the simulator with whatever default flight I have set up-- but have the simulator clock set to read "SYSTEM TIME" instead of "flight time", the sun doesn't show in the sky. All the glare and proper lighting of near sunset at the horizon, proper coloring at diff times of day, etc. will show correctly. But the disc of the sun is missing.

If I go into the date/time adjustment in the sim and change just the time (either H M or S) it won't do any good. But if I change date, year, month, or season, then the sun appears again. From there I can put it back to where I started and it shall display fine.

What's more: If I set the sim clock to open in "flight time" (so it reads whatever the default time was when I saved the flight), then the sun will display as it is supposed to.

I tried ditching the fs9.cfg file and letting it create a new one from scratch, but it did no good.

Any suggestions? Has anyone else noticed this behavior?

Thanks,

-- John

[b3burner]

Well... hmm... this is embarrassing. No sooner do I complain about the problem, it now seems to have fixed itself.

Fired up the simulator again, and now the disc of the sun shows up with my chosen default flight, with sim clock set to "system time"-- where it had not been working previously.

I could take guesses as to how I might have solved it, so if anyone else encounters the problem I described, you too might be able to fix it:

1. Cleared my cache-- using software I have called "Webroot Window Washer".

2. My Norton Anti-Virus released a few extra GB's into my C-drive that it usually takes up on-and-off through the week to check for stability. Can't explain it, but sometimes my C-drive will have 130GB of free space, then it slides down to 119GB, then jumps back up to 150GB... for no apparent rhyme or reason. Maybe the GB drop caused the sun to disappear? Really a long shot, but I have very few guesses. What's more, I don't run my sim on the C-drive, I run it through my expansion drive (I-drive)... so I really don't see how extra GB's available in the C should make any difference.

3. Put my old fs9.cfg in a storage folder, while I let the sim create a new one. Then deleted the new one and put the old one back in place.

4. Re-enabled a plug-in container for Mozilla Firefox that I had disabled yesterday. Though I can't imagine that my internet browser settings should have anything to do with a stand-alone flight simulator software.

5. Walked away from it and then came back? !!! Could doing nothing to solves one's problems in life, sometimes be the smartest move of all? I really don't know.

Again, if someone could shed light on this, I'd appreciate it.

[ronzie]

I always use flight time since I want the saved local time for the flight, not the time of my session. This insures if I change locations internationally I keep the desired time of day and season. I use a weather app and download the Z time real weather weather archive of the saved departure time. This provides the correct time of day effects of weather for the environment such as solar effects on clouds and winds, and even thermals in some instances.

If this is occurring at sunset or sunrise you might be suffering from a time zone difference using system time. FS does not cross time zones really well and there is freeware in the library here to correct for that. If you pause the sim and go to an overhead view in fair weather and then look at the shadows, they should give you a clue where the sun is located. Shadow length indicates the sun's elevation and the angle indicates the azimuth.

On a technical basis did you apply any software that changes sky/sun textures? There are some floating around.

[b3burner]

I always use flight time since I want the saved local time for the flight, not the time of my session. This insures if I change locations internationally I keep the desired time of day and season.

That's strange, because when I set it to flight time and open it up in say... San Francisco at 9am, and then I move to an airport in NY, it will read 12pm. You mean... you get it to retain the start up time... no matter what timezone you travel to?

I use a weather app and download the Z time real weather weather archive of the saved departure time. This provides the correct time of day effects of weather for the environment such as solar effects on clouds and winds, and even thermals in some instances.

Never heard of z weather before.

If this is occurring at sunset or sunrise

It had been happening anytime of the day that the sun was up... not just sun-r or sun-s.

you might be suffering from a time zone difference using system time. FS does not cross time zones really well and there is freeware in the library here to correct for that.

I downloaded a timezone program last year to correct alaska. I thik it took care of others as well. Can't remember the name of the guy who sponsored it, but he did a lot of timezone related stuff.

If you pause the sim and go to an overhead view in fair weather and then look at the shadows, they should give you a clue where the sun is located. Shadow length indicates the sun's elevation and the angle indicates the azimuth.

Yes, I'm pretty good at sun shadow analysis. I knew where to look for it, but it wasn't there. Well until my 2nd post on the subject that is.

On a technical basis did you apply any software that changes sky/sun textures? There are some floating around.

No sky sun textures. I'm mainly interested in keeping most stuff stock, except terrain mesh, airplanes, and some limited airports and/or cities. That way if I run into the prob I just described, it's easier to sort out the culprit if there's fewer variables to sift through.

Thank you for your ideas and input.

[ronzie]

With regard to using system time or flight time:

If I load a saved flight and move it to another time zone, yes, local time will change even using flight time but the reference Z time will be the saved Z time of the flight, not your system time. What I meant was if I load a saved flight say in UK that was saved with the local UK time, no matter what local time I have where I am running the session from (US CDT), it will load at the saved flight time I set for the UK local time. If I run with FS at system time from US CDT it would load at my current local time plus 5 hours in the UK location, not the flight time I saved. So, using flight time, if I load a flight that I saved at 1 PM local time at EGCC (Manchester, England), it will always load and use that time for the flight start no matter what real local time is at my residence.

Z time stands for Zulu time or G.M.T. (Greenwich Mean Time) or U.T. (Universal Time) meaning local time at 0 degrees meridian in Greenwich, England at the Greenwich Observatory. We used the Zulu time term in the military. Zulu is the pronounced phonetic alphabet for 'Z'. It is also noted in 24 hour time format.

Flight plans are filed for instance under U.T. since it takes for purposes of all references time zones out of the picture providing a single reference for controlled flight and calculations. ATC doesn't care about local time. If you look at weather METARS the date-time field has the first two digits as the day of the month at Greenwich, the next two the hour at Greenwich, and the last two the minutes at Greenwich when the reading was recorded anywhere in the world.

Here's a sample METAR using Z indicating GMT for day/time:
METAR KANE 160354Z AUTO 35003KT 10SM BKN080 22/18 A2999 RMK AO2

If you tune in to via short wave radio the U.S. Naval Observatory you'll hear reference time expressed as Universal Time meaning it is offset for Greenwich Mean Time. Digital time references for the U.S. are kept at the NIST and NIST-Boulder:
http://en.wikipedia.org/wiki/NIST
based also on atomic clocks (precision atomic decay based counter) adjusted every so often to the GMT which is set by astronomical means at Greenwich and the Naval Observatory.

http://en.wikipedia.org/wiki/Greenwich_Observatory
http://en.wikipedia.org/wiki/METAR#Example_METAR_codes
http://en.wikipedia.org/wiki/NIST

If you set the function in Windows it will grab a proxy of the GMT from a Microsoft site converter to set your system time at start up and once every 24 hours. I have a freeware atomic clock program I use instead and I use NIST-Boulder as first reference and NIST as a backup.

[b3burner]

Thank you Ronzie for your detailed explanation. I had forgotten that "z" stood for Zulu. Yes... of course, at any given moment Z-time will stay the same no matter what airport you jump your plane to and what the local time changes to. That I agree with... and yes that appears to be the case in all situations-- whether the sim is set to turn on the default flight at "system time" or "flight time".

Reading metars is just something I'm on the fuzzy edge of getting into and trying to learn-- especially since downloading the FSrealWX program and trying it out. I even downloaded separate OAT gauges, just so I can double check if the weather (at least the temperature data) that's being downloaded is accurate.

To me, it's fascinating to fly around and not just have every airport at sea-level read 59F and drop at a standard preset lapse rate with increased altitude. With the downloaded wx, I notice that sometimes temp lapse with altitude can reverse and actually get slightly warmer before cooling down again-- just in one specific thermal layer. And or it can be a completely different temp on one side of a mountain than another. For years I had run the sim clear skies standard atmosphere. Nice to see the change with the wx input. Renews my interest in all this for completely new reasons. Kinda' nice I say!

[ronzie]

OT but I have this to saw about Active Sky 6.5. If you are flying over steep hills or mountains depending on your altitude and wind direction and strength you'll get vertical drafts. Vertical drafts on landing are also simulated. Solar effects also affect mountain winds as well.

AS65 lets you load your flight plan into it and that helps it set up dynamic changes along the way. You turn it off in FS and let AS handle it.

There are later versions but for my pc AS65 performs nicely.

Using FS Real Weather by itself without the benefit of FSUIPC (AS registers certain features in it so it doesn't have to be a separate purchase.) you can get some turbulance and immediate wind reversals causing possible stalls as weather boundaries are crossed. AS via FSUIPC sets maximum wind rate changes by time and altitude.

Here is a complete route report from AS65 that you can get by entering a flight plan. I use the winds aloft to set performance parameters for FMC type aircraft. FSBuild, for one, reads that weather snapshot as well for corrected headings and fuel planning for certain aircraft. (Can't attach a formatted .pdf so here os plain text.):

AS COMPLETE FLIGHT PLAN REPORT - NOT FOR OPERATIONAL USE
DEPARTURE WEATHER FOR EGSS
EGSS 301650Z 22016KT 9999 SCT020 BKN024 17/12 Q1016
EGSS 301101Z 3012/3118 22008KT 9999 SCT030 BKN040 PROB40 3018/3020 BKN012 BECMG
3020/3023 6000 -DZ BKN006 PROB40 3023/3107 2000 BR BKN002 PROB40 3109/3112 9999
NSW SCT022
FL030: 211/28 (13.50) FL060: 256/35 (12.40) FL090: 257/34 (9.70)
FL120: 256/29 (0.50) FL180: 263/36 (-10.20) FL240: 278/39 (-21.50)
FL300: 281/48 (-38.10) FL340: 281/51 (-47.80) FL390: 275/58 (-57.50)
DESTINATION WEATHER FOR EHAM
EHAM 301655Z 24013KT 9999 FEW032 18/10 Q1019 NOSIG
EHAM 301006Z 3012/3118 25014KT 9999 FEW030 SCT040 BECMG 3017/3019 21008KT CAVOK
BECMG 3101/3103 SCT015 BKN025 TEMPO 3102/3108 SCT012 BKN015 PROB30 TEMPO
3102/3108 4000 -RADZ SCT008 BKN012 BECMG 3108/3110 SCT030 BECMG 3116/3118 16008KT
CAVOK
FL030: 225/23 (12.50) FL060: 237/19 (8.50) FL090: 262/20 (7.80)
FL120: 275/24 (2.10) FL180: 296/35 (-11.90) FL240: 295/47 (-22.50)
FL300: 301/55 (-38.40) FL340: 303/61 (-48.00) FL390: 299/69 (-57.80)
ALTERNATE WEATHER FOR
No alternate...
ENROUTE WEATHER
EGSH 301620Z 23014KT 9999 BKN037 20/11 Q1016
EGSH 301402Z 3015/3022 22012KT 9999 BKN030
FL030: 212/30 (12.70) FL060: 258/30 (12.50) FL090: 259/28 (9.40)
FL120: 264/29 (0.70) FL180: 271/37 (-10.40) FL240: 281/39 (-21.90)
FL300: 286/50 (-38.40) FL340: 286/55 (-47.80) FL390: 281/61 (-57.40)
EHVB 301625Z AUTO 25014KT 9999NDV FEW028/// SCT039/// 18/12 Q1018 BLU
EHRD 301007Z 3012/3118 25014KT 9999 FEW030 SCT040 BECMG 3017/3019 21008KT CAVOK
BECMG 3101/3103 SCT015 BKN025 TEMPO 3102/3108 SCT012 BKN015 PROB30 TEMPO
3102/3108 4000 -RADZ SCT008 BKN012 BECMG 3108/3110 SCT030 BECMG 3116/3118 16008KT
CAVOK
FL030: 220/24 (12.70) FL060: 259/18 (10.90) FL090: 273/19 (8.40)
FL120: 270/23 (2.10) FL180: 293/35 (-11.40) FL240: 292/42 (-22.20)
FL300: 297/53 (-38.50) FL340: 297/58 (-47.80) FL390: 295/65 (-57.40)
WINDS ALOFT REPORT BY WAYPOINT
ID FL060 FL090 FL120 FL180 FL240 FL280 FL340 FL390
EGSS 256/035 257/034 256/029 263/036 278/039 281/048 281/051 275/058
REDFA 258/030 259/028 264/029 271/037 281/039 286/050 286/055 281/061
TULIP 259/018 273/019 270/023 293/035 292/042 297/053 297/058 295/065
EHAM 237/019 262/020 275/024 296/035 295/047 301/055 303/061 299/069
NAVIGATION LOG
TO DIST MC MH WDIR WSPD TEMP TAS GS ETE
EGSS
84.1 82 79 281 51 -47.8 450 497 10
REDFA
52.5 73 68 286 55 -47.8 450 493 6
TULIP
33.5 97 94 297 58 -47.8 450 503 3
EHAM
----- -----
170.1 19m
0.32H
Average Route Winds for 35000ft: 284/53


Formatting is poor but you can see METARS, winds/temperatures aloft at departure and destination, and forecasts (TAFS), plus their weather related flightplan at the end (which I don't use too much). You can observe wind and temperature changes which might indicate flying through a frontal passage (which changes with altitude - use the winds aloft by waypoint at a specific altitude for comparison).

You might find this interesting:
http://www.faa.gov/library/manuals/a...apter%2012.pdf

I don't see much at the FAA site regarding weather basics such as frontal characteristics, cloud types, etc., regarding weather problem avoidance and creating your own forecast from the charts available. Things like thunderstorm characteristics, where they are likely to be, turbulence in CB clouds, etc.

For real world weather in the US I get weather information charts from wunderground.com (as well as radar and stats).

http://classic.wunderground.com/US/R.../2xFronts.html is handy but click those of interest in the left column.

and:

http://classic.wunderground.com/Aviation_Maps/ scrolling down the page for specific chart types thumbnails.

This way you can look for "interesting" weather areas.