Boating snobs... Pah!

 

For what it's worth: I've been using AS2012 in direct weather control mode since it came out (and ASE and ASA before that), and have never encountered TAT issues at all. The very occasional barometric pressure or wind shift glitches, yes, but temperature problems... no, sir. I don't know if REX and Opus offer a corresponding mode of operation, but if you want consistent weather conditions in tubeliner territory, DWC is the way to go.

I can tell you categorically that I have encountered this problem with the LDS 767 - and also the PMDG MD11 and the PMDG JS41.  

 

Those incidents happened while using various versions of HiFi's ActiveSky.

 

Subsequently, I've switched to OpusFSX, which has coincided roughly with the reign of the PMDG 737NGX.  Personally, I haven't seen the problem with that combination but a few others have reported it.  

 

I conclude that this is an inherent FS problem.  It doesn't affect less sophisticated add-on aircraft because they don't model engine performance sufficiently well to show the results.  Any of the leading types are going to be prone to it though.

I've had the s-turns and pressure/temp/-wind shift problems with wx from REX (unusable), Opus and AS2012 but never with FS Global Real Weather.

 

To be fair, Opus was in an early stage when I last used it and with AS2012 it got solved when I used the recommended settings from one of the beta-testers who frequent this forum.

 

I landed on FSG wx because I like their depiction and their no fuss GUI. I run all WX engines (except Opus) networked from a laptop.

How about 100% of the time glitch when using the 737NGX and a 0% of the time glitch when using the Level-D 767-300

 

I had the TAT problem when flying the NGX and the LevelD using the FSX default weather or FSINN weather, but when I use Active Sky weather the problem goes away.   I was informed that it was a problem with the FSX weather engine.

Honestly guys ... I too worship at the alter of the Gods that are PMDG ... but I'm coming from a unique position of installing the exact same software on three different rigs ... my original Duo Core 8400 Wolfdale at 3.0GHz, my i7 4700MQ at 2.4GHz software development laptop and my new rig ... an i7 4770K at 4.2 GHz ... and I experience that same problems throughout ... with and without weather. 

 

The last thing I want to hear is an allusion to my inattention to scientific detail ... no disrespect intended Mr. Rodgers.

 

C. T.

 

I don't think you're listening to some of the responses here.

 

If you're using OPUS then that issue may be down to that, I uninstalled it a while back in favour of activesky2012.

 

Disable FSINN weather

I don't think you're listening to some of the responses here.

 

If you're using OPUS then that issue may be down to that, I uninstalled it a while back in favour of activesky2012.

 

Disable FSINN weather

if you would  have  read his post  on post 8,   he has tried  them all  with the same results

if you would  have  read his post  on post 8,   he has tried  them all  with the same results

 

Actually, he said he'd tried different weather programs. OP still hasn't tried just using the built-in "clear weather" theme, no add-ons etc and do an offline flight. When he does, I'm sure TAT will have normal/expected readings.

 

 

if you would have read his post on post 8, he has tried them all with the same results

 

But, he is trying to blame the NGX and it is not the NGX, but the weather engine within FSX.  Make sure that you have real world weather checked in FSX and use Active Sky 2012.  I did and now do not have the problem.  This is what everyone is trying to tell him.  It has worked for everyone else, so, I do not think that it is a problem with the aircraft software, but the FSX program itself.

Yeah, that's what I've noticed.  The cleared weather really has to be tried before we can go much further.

 

Perhaps he hasn't had time to hit the sim yet.  I post mostly at work, after all, and I don't have time to just bust open the sim.  Perhaps a little of the impatience came from wanting to mentally solve the issue without having to jump in the sim.  I know that's frustrating for me, if someone's help is contingent on getting in the sim, and I can't get in the sim for some time.

 

 

 

Cool pic Kyle, where is that?

 

Sitting in the Potomac River right by DCA.  Oddly enough, our engine quit right next to the airport.  The family taking me out was apologizing profusely, but I just replied: "I'm on a boat, with some people I enjoy being around, who have provided me beer and food.  And I'm in the perfect spot to watch airplanes.  Not a bad way to spend a Sunday, I'd say."

 

 

Here in Norway it has been around 27-30c degrees during the last weeks, so finally my boat get to earn its keep. Rare event for us Scandahoovians, as I am sure you know from when you were here.

 

Yep.  Last two times I was there I got the pleasure of rainy April and frigid January (Hommersåk and some random cabin in Sirdal, respectively.)

I don't believe that it can't be fixed at all. The 3rd party add-on devs should do a bit of research on upper flight level temperatures, and look to see what the range of values are to the 90th percentile, then simply normalize values that fall outside of that range.

 

It really is ridiculous that everyone says it is an FSX bug when the weather programs are writing this value directly! It is actually a data source bug!!!

 

Garbage in, garbage out. Time to get smart and do some real-time data analysis or simple bounds checks at least!!! If the values in the data are trash, revert to an internal model that provides realistic values, based on a median, or at worst, Standard Day!

 

Best regards,

Robin.

Firstly, this topic should be concerned with the inability of FSX to maintain its ambient air temperature (that is the Static Air Temperature (SAT) or Outside Air Temperature (OAT)) and not the Total Air Temperature (TAT).

 

No weather engine can control the TAT, it is a purely calculated value, calculated internally by FSX based 'largely' on its current ambient air temperature (that is the current SAT or OAT) and your current airspeed (as a Mach number).

 

The TAT cannot therefore be targeted or controlled directly by any weather engine. Nor can the ambient air temperature be controlled by any weather engine, the only thing a weather engine can do is set appropriate target temperatures for each altitude zone (a limited number at a time) for FSX to try and follow or try to adhere to.

 

FSX, as most people here will attest to, can struggle to meet these targeted 'ambient' temperatures. Fortunately this occurs on very few systems. One sure way to eliminate the problem is to stop FSX recalculating and making any attempt to readjust to new targets, something that can be done by injecting 'global' or mostly 'globalised' weather.

 

As far as the OpusFSX Live Weather Engine (LWE) is concerned, which attempts to inject RW and highly varied weather patterns, there are a number of steps that can be taken to virtually eradicate the ambient temperature drift problem. We take the basic steps listed below and have never encountered a single problem on any system including lower performance laptops.

 

The first thing users should do is set all weather defaults in all the weather related dialogs and then tick the 'Adjust Options Automatically' and 'Adjust Sim Friendly GRIB Data' options.

 

The second thing that should be done is to ensure you have set the Weather Update Frequency and Distance to something very similar to the recommended settings, which are now every 30 minutes and/or 160km.

 

Trying to elliminate weather updates by setting these options to high values, or disabling the weather updates for extended periods of time, will undoubtedly cause problems on many systems, leading to both the ambient air temperature and ambient winds drifting inside FSX. This is caused by FSX drifting off and starting to do its own thing and ignore its previous, fairly localised, wind and temperature targets.

 

Finally, users should ALWAYS specify their intended Destination and most importantly specify their intended 'Max Cruise Altitude'. Specifying a 'Max Cruise Altitude' of 6000 feet or more will ensure GRIB forecasted data is used and not just simulated upper winds and temperatures.

 

There are also a number of other stabilisation options which will help on those few systems that are still troubled by this FSX problem. The 'Use Maximum Stabilisation' will extend the normal stabilisation options to include surface pressures and temperatures. Finally, there is a separate 'Stabilised GRIB Data' option in the Downloads dialog, this must be manually set and will force the GRIB forecasted data to remain static throughout the flight.

 

The above stabilisation options make as much of the weather stable or as static as possible without resorting to globalised weather injection. So you will still be able to see the various weather patterns, approaching weather fronts etc. whilst trying to minimise any upset to FSX during the weather updates.

 

On most systems that suffer from high ambient air temperatures, and hence a high calculated TAT reading inside FSX, the problem results from attempting to fly with too few weather updates. The lack of weather updates allows FSX to drift away from its previously injected targets. Once FSX has drifted so far away from any targeted temperatures and winds it can decide to ignore any new targets specified during the next and subsequent weather updates.

 

So use the above recommended sim friendly and stabilisation options, nearly all of them can be set automatically for you, and whatever you do not inhibit weather updates for too long and let FSX get out of 'targeted' control.

 

I hope the above is helpful.

 

Stephen

You can test this for yourself - FSX will use a standard temperature lapse rate between temperature layers (except between layers), so if only one layer is defined, the rest of the temperature values follow the standard temperature lapse rate to infinity.

 

The problem is not residing in FSX at all, but in the data being sent to the sim.

 

Yes, TAT is a computed value, but it does not absolve the base temperature from being the source of the problem.

 

Once again: garbage in, garbage out.

 

If there is any doubt as to the veracity of my claim, please check the following calculation for standard lapse rate and TAT computation based upon Mach number for ambient conditions:

 

 

 

T_s = 288.15 - (0.0165 * sim->abs_alt * 0.3048);

// Compute Mach number and ram rise
lss = sqrt(gamma * R_sp * T_s); // m/s
lss = lss * 1.94384449; // m/s to kts
M_a = sim->tas / lss; // Compute Mach

RR = T_s * ((gamma - 1.0) / 2.0) * e * pow(M_a,2.0); // Total ram rise, °K

 

T_s = Static temperature (assumes standard lapse rate)

lss = Local Speed of Sound

M_a = Mach number

RR = Ram rise (absolute)

 

Note the role of static temperature in the last calculation. QED. Bad static temp (as per the problem in FSX) results in ultimately wrong TAT value.

 

Best regards,

Robin.

Sorry that is just rubbish. The data is derived from the downloaded GRIB global forecast data and adjusted to ensure it is 'sim friendly'.

 

Nothing is hidden in the OpusFSX weather engine, there is a VAST amount of information available at your finger tips in both reports, on screen weather reports, and now in the Live Weather Assistant and smaller Weather Maps. The on screen weather reports also SHOW you 'on screen' both the ambient wind and temperature targets along with the ambient temp and calculated TAT. The INFORMATION is there for you to see and see for yourself that it is 100% correct. Nothing is hidden.

 

So your statement is totally unsubstantiated and complete garbage itself.

 

Look at the data yourself. All the wind and temperature targets are there for you and everyone to see.

 

Look at the weather reports. Examine the Opus WeatherReport.txt file, its all there.

 

Stephen

 

 

Firstly, this topic should be concerned with the inability of FSX to maintain its ambient air temperature (that is the Static Air Temperature (SAT) or Outside Air Temperature (OAT)) and not the Total Air Temperature (TAT).

 

I agree, but somehow i doubt that will be fixed anytime soon...  :unsure:

Thanks for the FSInn ... see picture below ... is this where you guys recommend turning off weather?

 

https://www.dropbox.com/s/m6hsitg4zcst0rz/FSUIPCOptionsAndSettings.jpg

 

Thanks,

 

C. T.