Real Environment Xtreme cruise temperature problem

[Dominik Trybuchowicz 11337]

Hello everyone!

Recently I have installed an update for my REX and I also downloaded the 'Overdrive' from REX's website. My problem is that when I am at cruise flight level (FL370 for example) the TAT is about -25 Celsius. It seems to be very high and actually when compared with enroute weather charts, it is about 40 Celsius degrees higher.

 

Has anyone had this problem before? Does anyone know how to solve it?

 

Thank you very much in advance

 

Dominik Trybuchowicz

[William Sequeira 1192651]

Same problem. It will be fine, then just change on you....it should never be that high really. It kills engine performance and kills the flight.

 

I bought FSUIPC, but don't really know the settings is any that would help.

[Charan Kumar]

Which weather engine are you using? FSX, REX or FSInn (if using FSInn)?

[Wycliffe Barrett]

More importantly which aircraft are you using.

 

pitot heat anyone.

 

Fsinn weather has a well known bug above fl245 which will cause this effect.

 

Wycliffe

[Andreas Fuchs]

Well, also keep in mind that "TAT" stands for Total Air Temperature. This is the measured outside air temperature, which is not corrected for frictional heat that comes from the air molecules being thrown against your plane (and also against your temperature probe) at high speed! When you cruise at around Mach 0.80 your temperature will rise (called ram rise) by roughly 20 degrees Centigrade. If the SAT (Static Air Temperature) is -60 degrees C, you will read about -40 degrees C on your TAT-indication. If you fly slower, the rise will be lower. So, a TAT of -27 deg C means that the SAT is about -47 degrees C, plus/minus a few degrees and that is well possible.

 

http://en.wikipedia.org/wiki/Total_air_temperature

[Dominik Trybuchowicz 11337]

Thanks a lot for all your replies so far!

 

Same problem. It will be fine, then just change on you....it should never be that high really. It kills engine performance and kills the flight.

 

I bought FSUIPC, but don't really know the settings is any that would help.

 

I am not sure whether I understood you correctly. Are you saying that you have solved this problem? Or that you don't know how to solve it yourself?

 

Which weather engine are you using? FSX, REX or FSInn (if using FSInn)?

 

I am using REX. When I launch FSInn, I always set the weather to CAVOK, then I launch the weather in REX weather engine by clicking 'Load WX'. Also, when after doing this I check the weather by going into 'World' and then 'Weather' in FSX, 'User defined weather' is the one selected.

 

More importantly which aircraft are you using.

 

pitot heat anyone.

 

Fsinn weather has a well known bug above fl245 which will cause this effect.

 

Wycliffe

 

I am suing PMDG 737NGX and the pitot heat is always on. Also, I am aware of the bug you have mentioned. As far as I know, there is a problem that instead of for example having -45 Celsius, you have +45 Celsius. This bug still appears in my flightsim as soon as I click 'VATSIM' in FsInn weather, and that's why I always set it to CAVOK before loading weather through REX weather engine.

 

Well, also keep in mind that "TAT" stands for Total Air Temperature. This is the measured outside air temperature, which is not corrected for frictional heat that comes from the air molecules being thrown against your plane (and also against your temperature probe) at high speed! When you cruise at around Mach 0.80 your temperature will rise (called ram rise) by roughly 20 degrees Centigrade. If the SAT (Static Air Temperature) is -60 degrees C, you will read about -40 degrees C on your TAT-indication. If you fly slower, the rise will be lower. So, a TAT of -27 deg C means that the SAT is about -47 degrees C, plus/minus a few degrees and that is well possible.

 

http://en.wikipedia.org/wiki/Total_air_temperature

 

I thought of this too, but I wasn't sure how much that would affect it. As you said, the difference between TAT and SAT is roughly about 20 Celsius degrees, therefore my TAT of -25 Celsius (which I have just now cruising at FL380) would work out to be about -43 Celsius. This is still significantly higher than what it is supposed to be according to this chart: http://131.54.120.150/index.cfm?section=dspImage&image=21OWS_EUROPE_MODEL-DATA_UKMO-GLOBAL_WIND-TEMP_FL390_12_00Z.png (I am over southern Spain at the moment)

[Dominik Trybuchowicz 11337]

Ok, I have just checked my SAT in the FMC and it actually says -52 Celsius, which seems quite similar to that one in the chart I have posted. However, this is because I am flying near the Northern part of Africa, where the temperature is slightly higher than in the rest of the Europe according to the chart. I still recall having my TAT at about -25 Celsius at FL360 over UK where the temperature is lower than the one over Northern Africa as shown in the chart. Later on today, I might fly over UK and then I'll check both, TAT and SAT and I'll let you know

[Andreas Fuchs]

Hi Dominik,

 

alright, what tool are you using for the generation of weather? Can you lookup the temperature that is supposed to be there? In ActiveSky you can do that, I am not familiar with any other program, though.

[Wycliffe Barrett]

If your using the REX weather engine you do not need to set FSinn to Cavok and then go to real world weather in FSX. I think that is where the problems lie.

 

In your rex settings you can set it to use vatsim weather. The process then is when you start up FSX REX weather engine will start automatically and start to install weather.

 

Join Vatsim via FSinn and when you look at your minipanel there should be no cloud and sun depiction next to VATSIM label and you do not go into FSX and start real wordl weather in there. It is a fully automatic process aslong as you have your settings right in REX.

 

Works for me everytime and all trhose people who I have setup in REX aswell.

 

Good Luck

 

Wycliffe

[Charan Kumar]

To add to what Wycliffe is saying, in the FSInn settings, you can disable weather, do just that. Pressing CAVOK will only cause a conflict between weather engines.

[Dominik Trybuchowicz 11337]

If your using the REX weather engine you do not need to set FSinn to Cavok and then go to real world weather in FSX. I think that is where the problems lie.

 

I set it to CAVOK so that there is no cloud next to 'VATSIM' in FsInn. And when I go into the 'World'->'Weather' in FSX I do NOT change anything there. I only mentioned that as a cross-check of what is set there.

 

To add to what Wycliffe is saying, in the FSInn settings, you can disable weather, do just that. Pressing CAVOK will only cause a conflict between weather engines.

 

And adding on the top of what I said above, now instead of setting the weather too Cavok to make sure it is not set to VATSIM, I have disabled the weather.

 

Actually checking the SAT now (in FMC), it is quite similar to the one on the weather charts, so it is just this big difference between TAT and SAT that was confusing me.

 

However, I am frustrated ( even more than that) about what is happening to my plane in cruise. For example the wind changes and I get a crosswind from one direction, the plane starts banking towards the wind and it reaches a 60 degree bank when the autopilot disconnects! This is not normal! Here is a screenshot:

[Charan Kumar]

There are few recommended settings for FSUIPC controlling the wind smoothing etc, so you don't get such violent changes, but that might only be possible with the registered version I think.

 

The FSX Real World Weather with updates works fine actually. So you can install REX textures, but don't use the REX weather engine. See if that gives you a better combination. Only disadvantage is there will be a few situations where it might not match very closely to VATSIM weather, as updates are still playing catch up.