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MadDriver

Still getting really high TAT

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I was flying out of Mexico City and the TAT kept climbing as I climbed. It was +33 c at FL200. I was having a hard time keeping the aircraft going up. I'm a RW air traffic controller, so every once in a while I get to ride up front in the jumpseat, and last weekend, I paid special attention to the TAT during the flights when I went down to Minneapolis. It was nice to see that, at a cruise of FL350, the TAT was around -28 to -33, which was around the amount I was getting in earlier version of OPUS at -25.

 

I'm using version 2.70.8 and FSINN. I have disabled all weather on FSINN. Is there something else I should try? It's frustrating to have temps that high...

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I'll try that PMDG fix from a post I had earlier this month. Forgot about that, and we'll see if that works tomorrow. Any update on that?

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Tried deleting the PMDG DLL files from the FSX file. Still not working. I am currently stuck at FL260 because my plane will not climb at +30 c.

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Maybe it's a Mexico thing. Right now I'm cruising from KSMF to PHOG at FL360 with a TAT of -17 c. Target and ambient are both at -46 c. I'll do another Mexico flight sometime soon and see what happens.

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OK, we don't have any control over the TAT, it is calculated by FSX or the aircraft sim, but I would be interested to see what the 3 values are.

 

Regards

Cheryl

 

The target and ambient temperatures are the SATs, that's all you can set. The TAT is a calculated value in the sim which should always be higher than the SAT due to compressional heating.

 

Your values seem perfectly fine to me. Absolutely perfect. Best look at a description of how the TAT is measured in real life and the effects of compressional heating as the airflow is brought to a standstill for the TAT to be measured ... Just like a bicycle pump the air heats up. 30 degrees of heating seems OK to me, depends on a lot of factors though.

 

But once again, this is a temperature calculated inside the sim and can not be controlled by the LWE.

 

Stephen :-)

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Hi Stephen,

 

I face a similar situation:

Currently I am cruising on my flight EHAM-KLM83S-WADD at FL370, just passing VNKT.

 

The OPUS weather report window (BTW: what does the [31, 30] mean?) states...

1 - World Wide GRIB Data, Wednesday, 19.December 2012, 0000Zulu

2 - Tropospause Height 50273 Feet, Temp -70, Wind 263/100

3 - FL420: Temp -59, Wind 261/119

4 - FL380: Temp -51, Wind 264/115

5 - FL340: Temp -42, Wind 269/107

...

 

TAT is at +21, SAT -17, but FL370 should give us SAT -49, should it not?

 

Strange meanwhile I read...

1 - World Wide GRIB Data, Wednesday, 19.December 2012, 0000Zulu

2 - Tropospause Height 54793 Feet, Temp -75, Wind 261/90

3 - FL420: Temp -59, Wind 259/112

4 - FL380: Temp -51, Wind 264/108

5 - FL340: Temp -42, Wind 270/102

...

 

TAT is at -11 (better now), SAT -43, but still FL370 should give us SAT -49, should it not?

 

Please, one of the real jockey might tell us whether that high TATs do occur.

 

Thanx in advance.


Andreas Berg
pmdg_j41_banner.jpgpmdg_trijet.jpg

PMDG 737NGX -- PMDG J41 -- PMDG 77L/77F/77W -- PMDG B744 -- i7 8700K PC1151 12MB 3.7GHz -- Corsair Cooling H100X -- DDR4 16GB TridentZ -- MSI Z370 Tomahawk -- MSI RTX2080 DUKE 8G OC -- SSD 500GB M.2 -- Thermaltake 550W --
 

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Yes. the targets should have resulted in a SAT of about -49. When you said it was -17, was this taken from our other weather reports which give you the current target requested of FSX and the actual ambient and TAT from current in FSX.

 

In my opinion the high TAT was calculated as a result of FSX's high SAT. But I would be interested to know whether you took your readings from within FSX (our weather report windows) or from inside your aircraft's sim. Something is not reponding to the target temperatures set within FSX.

 

The [31, 30] is the current weather cell [row, col] indexes, they identify the location within the Opus weather map and injected weather region, after you update the weather your location will be [30,30], in the centre.

 

In the next beta I shall be improving the speed targets and gradients, FSX seems to suffer more problems when it encounters strong upper winds and starts loosing sight of its targets.

 

Regards

Stephen

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But I would be interested to know whether you took your readings from within FSX (our weather report windows) or from inside your aircraft's sim.

 

Hi Stephen,

 

SAT and TAT I read from the MD11's displays, right now (FL370) SAT -42°C, TAT -10°C.

The weather report window from today, 'Upper Atmosphere, Latitude N20, Longitude E93' 17:19z reads now

...

4 - FL380: Temp -47, Wind 261/45

...

The other window 'METARs at Current Location' shows

6 - Ambient Temp -41 TAT -10.

 

Ok that fits (little rounding errors) except for the 4 - FL380: Temp -47, Wind 261/45...

 

Ahh, that's taken from the GRIB data right?

But should not 12:00 zulu be available now?


Andreas Berg
pmdg_j41_banner.jpgpmdg_trijet.jpg

PMDG 737NGX -- PMDG J41 -- PMDG 77L/77F/77W -- PMDG B744 -- i7 8700K PC1151 12MB 3.7GHz -- Corsair Cooling H100X -- DDR4 16GB TridentZ -- MSI Z370 Tomahawk -- MSI RTX2080 DUKE 8G OC -- SSD 500GB M.2 -- Thermaltake 550W --
 

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Firstly, FSX can be several degrees away from its target temperature (6 degrees is not unexpected) some systems are better than others but FSX is not that perfect. You will also find it may lag behind its targets when climbing or descending. We are forever tweaking this and that to squeeze the last bit of performance or stability out of FSX, which is especially fickle when presented with RW changeable and varied weather.

 

Secondly, you are right, all target wind and temp data above FL200 is taken directly from the GRIB forecast data. These are forecast in cycles, themselves posted anything from 6 to 9+ hours after the cycle time. But each cycle also includes forecast data for up to 360 hours. The LWE just tries to obtain the latest cycle but if that is not available it tries for the previous cycle. So the 1200Z cycle might be ready in about 2 hours time, but you never know.

 

Regards

Stephen :-)

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Thanx, Stephen.

Got it know. Anyway amazing the shitloads of data you are managing...

all regions, all altitudes..., winds and temps

 

Some more questions:

1. Why do you present the tropopause? Is it informatively only?

I know with the tropopause the temperature does not decrease so much anymore...

For interpolating the data it is for sure a must to take into account.

 

2. I just overflew Bangkok, but the METAR was not displayed, but the window did overflying UMGG (Gomel, Belarus) a couple of hours ago. Why?

 

Thank you in advance.


Andreas Berg
pmdg_j41_banner.jpgpmdg_trijet.jpg

PMDG 737NGX -- PMDG J41 -- PMDG 77L/77F/77W -- PMDG B744 -- i7 8700K PC1151 12MB 3.7GHz -- Corsair Cooling H100X -- DDR4 16GB TridentZ -- MSI Z370 Tomahawk -- MSI RTX2080 DUKE 8G OC -- SSD 500GB M.2 -- Thermaltake 550W --
 

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1. The tropopause info, its forecasted height in that lat/lon is useful info for some flight management systems.

 

2. If you are referring to the Local Area report. That identifies the nearest weather insertion point to you with the listed weather generally appearing to the NW of that point. It could simply have been that the airport was just outside that weather cell. Perhaps I will have to add a Nearest METAR site report in the future. One handy tip is to enter a site en route as an alternate if you are interested in the weather there. Then display the relevant alternate weather report.

 

You're right about the weather data, I think the LWE now holds over 5 times the amount of weather data than FSX can even handle at any one time.

 

Regards

Stephen

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One handy tip is to enter a site en route as an alternate if you are interested in the weather there. Then display the relevant alternate weather report.

 

How do I enter destination and Alt x?


Andreas Berg
pmdg_j41_banner.jpgpmdg_trijet.jpg

PMDG 737NGX -- PMDG J41 -- PMDG 77L/77F/77W -- PMDG B744 -- i7 8700K PC1151 12MB 3.7GHz -- Corsair Cooling H100X -- DDR4 16GB TridentZ -- MSI Z370 Tomahawk -- MSI RTX2080 DUKE 8G OC -- SSD 500GB M.2 -- Thermaltake 550W --
 

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you can try to "disable weather by default" in the control panel settings, and fly with real weather from FSX...

 

... or you can do what I do: fly with "almost real weather", it works... hehe

 

you connect to VATSIM (or whatever) in the control panel, wait 10 seconds until weather refreshes,

then you switch weather (the little cloud icon) to some other unused connection, like NET3, NET4...

 

and go to advanced weather on FSX menu, and change the temperature just 1 degree, down or up...

it will keep that first refreshed weather, but temperature will drop as expected in your climbing...

 

you can refresh your weather again when descending, below 10000ft!!


Gustavo R. Borghetti

JET TRANSPORT DIVISION - JTD1099

VAFS Featured Virtual Airline

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