4.232 744X KSEA-KMCI

[downscc]

Much improved, thanks.

FSX SP2 flying PMDG 747X with ASX 1106. Picked a route that should have some shifts for tests. Departure and climb very smooth, some minor wind velocity fluctuations (2kts). At FL360 winds varied from 275/44 to 284/59 over several hours, all wind variations were smooth.

During descent winds/heading were not a problem with IAS fluctuated excessively. This I do not understand. At one point descending through 5000 the IAS was 170 with jumps to 190 that were very quick and about 2 sec apart; however, the wind was steady, pressure/altitude smooth, go figure.

I used FSUIPC settings to 1deg/kt change per 3 sec., no turbulence in either ASX or FSUIPC, ASX smoothing off, no enhanced route coverage.

Having reported this, I'd like to add that this was a major improvement to the violent shifts that I have experience before on many arrivals.

The IAS jumping around like that is really odd.

[Pete Dowson]

During descent winds/heading were not a problem with IAS fluctuated excessively. This I do not understand. At one point descending through 5000 the IAS was 170 with jumps to 190 that were very quick and about 2 sec apart; however, the wind was steady

Where were you observing that the wind was 'steady'? Did WeatherSet2 show any wind turbulence, variance or gusts? With that sort of variation I would expect it to mention gust speeds of up to 20knots over the base wind speed. Gusts are more likely to be widely spaced, like 2 secs -- turbulence is very quick, frame-by-frame or faster, and less drastic. And gusting is more likely in the lower (usually surface) wind layers.

The IAS jumping around like that is really odd.

I'd need to know the wind layer details -- gust, turbulence, variance -- before agreeing or disagreeing with that. The two need to be compared, each time there's anything out of the ordinary. Gusts will change the IAS reading noticeably.

Regards

Pete

[downscc]

WeatherSet2? Not sure what this is.

I have tried to disable every source of turbulence. ASX Wind Turb = 0; FSUIPC has turbulenc, gusts and variance suppression checked.

It's been two hours, but current wx at KMCI is pretty calm: Surface 358/6, 060 337/14, 120 261/36 and 180 249/60 (no gusts).

Only IAS was changing, the wind vector in the aircraft and FSX agreed (using Shift-Z) that the winds were not gusting. The IAS spikes were also shown by FSX. That is what I find interesting. IAS variance but no wind variance. It was so odd that I looked at it very closely (I've been flying for 35 yrs).

[Pete Dowson]

WeatherSet2? Not sure what this is.

The program originally supplied within the FSUIPC ZIP package which allows you to view all the weather data at the aircraft, or at any weather station or LAT/LON. By default it shows weather at aircraft position. It is also able to manipulate weather at weather stations, but that is not relevant here.

For FSX it has been packaged separately and has been available, along with WeatherSet (the global weather manipulator, mainly for FS2002 and before) in the FSX Downloads Announcement above -- for 18 months now. If you scroll down past the (rather long) FSUIPC4 update details you'll find it, and a lot of other stuff you may not have known existed. ;-)

I have tried to disable every source of turbulence. ASX Wind Turb = 0; FSUIPC has turbulenc, gusts and variance suppression checked.

Yes, but they suppress the stuff that FSUIPC has control over. The ACTUAL weather details, if you read them, might show that FSX was doing stuff beyond FSUIPC's (current) control. That's the point of this testing -- to find out. Unfortunately without correlating what you see with what FSX tells us it is doing (i.e. the weather reports as viewable in WeatherSet2), we are none the wiser.

Only IAS was changing, the wind vector in the aircraft and FSX agreed (using Shift-Z) that the winds were not gusting. The IAS spikes were also shown by FSX.

Where else did you see that the "IAS was changing" if not shown by FSX? Do you have another monitor for this?

I don't know whether FSX's gust simulation is made to reflect in the wind vector/Shift+Z values -- those are certainly affected by anything FSUIPC does. But in previous versions of FS, none of gusting, turbulence or variance affected wind indicators, because really, in a real aircraft, these do not show the ACTUAL wind (how can they?) but the computed wind calculated from the observed tracking error using one or more of GPS, IRS or VOR triangulation position following. That takes time and is not subject to "twitching".

The fact that FSUIPC's method of inducing oscillations for these effects also twitches the wind indicator is unfortunate. I cannot avoid that I'm afraid. But FS itself can avoid such things, of course.

That is what I find interesting. IAS variance but no wind variance. It was so odd that I looked at it very closely (I've been flying for 35 yrs).

Gusts are taken to be only wind speed changes, "Variance" is the term here used to mean directional variability. Often I would expect them to go hand in hand, but they are simulated separately even when they occur together.

Regards

Pete

[downscc]

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Poorly worded.. both airspeed indicators in the bird (tape and steam gauge) and the Shift-Z info line indicated IAS spikes.

Next test I will use the weather tool you mention.

Sure would love to see this solved... I'm excited with the progress that has been made. Thanks.

[Pete Dowson]

Sure would love to see this solved... I'm excited with the progress that has been made.

I've made some changes to the way the turbulence is handled. Please see if version 4.233, now available in the FSX Downloads announcement, is better.

Regards

Pete

[downscc]

Wilco... I will this afternoon after the honeydo list.

This a.m. I got the WeatherSet2 and ran it along with a short test flight at KDFW where winds vary from 141/5 on the deck to 240/113 at FL330 with a big change in velocity just below FL300. The good news is that FSUIPC4 4.232 worked perfect, WeatherSet is a really handy tool. The bad news is I didn't reproduce the gusts that I had on the flight into KMCI last night.

Thanks,

[Pete Dowson]

The good news is that FSUIPC4 4.232 worked perfect

FSUIPC 4.234 is now up and waiting for you. The main change is that it tries much harder to eliminate the silly spurious thin wind and temperature layers.

[LATER]

I spotted a couple of areas where I could improve things somewhat. So, please move on to version 4.235 for further tests.

Regards

Pete