FYI PMDG 747X eratic autopilot: Turbulence suppress

[mtjoeng]

when fsuipc connected, my pmdg 747X could not keep proper LNAV track, 'drunken a-pilot syndrome'

deleted DLL.XML and my pmdg 747X Behaved OK

after trial and error

- disabling any FSX controllers, all handled by FSuipc

- deleting all joystick/joke buttons assignments in FSX

- delete Mouse Yoke (and View) assignments

- all weather enhancements FSuipc off

- PMDG 2D-Panel performance higher

'Winds' page, 'Suppress these wind effects':

turbulence suppress: check enable

et voila, problem solved

gusts and variance, no problem

Allow changes to FS own weather, no problem

Wind Smoothing, no problem

seems FSuipc related, but shouldnt, how come turbulence suppress is a factor?

PMDG 747X, latest patch v2.10.0040

FSuipc 4.316 (bad AP on previous version, 4.30, 4.303)

FSX on Vista64, MSI 8800GT/512GB (see signature)

mt

[Pete Dowson]

when fsuipc connected, my pmdg 747X could not keep proper LNAV track, 'drunken a-pilot syndrome'

deleted DLL.XML and my pmdg 747X Behaved OK

FSUIPC doesn't do anything on its own. It acts as an interface to other programs. Check your add-ons. There are also options in FSUIPC if it is use registered, which can do things for you, of course.

seems FSuipc related, but shouldnt, how come turbulence suppress is a factor?

Please scan the many many threads and discussions there have been on this very topic, for the last six months at least. Not for a while now though. You must have missed them all.

The PMDG 747 test pilot has tested FSUIPC4's simulated turbulence and found it realistic. An autopilot cannot fully cope, in reality, with turbulence above "moderate", so if you find yourself in such turbulence you should, as real pilots do, seek a higher or lower flight level to avoid it.

if you don't care to do things realistically, please just disable turbulence.

Note that if you use ASX and also have it set with certain options it can exacerbate things. You should not try to have both simulating turbulence.

Pete

[mtjoeng]

Re: FYI PMDG 747X eratic autopilot: Turbulence suppress

An autopilot cannot fully cope, in reality, with turbulence above "moderate", so if you find yourself in such turbulence you should, as real pilots do, seek a higher or lower flight level to avoid it.

Pete

interesting, thx

no addons running though

with everything weather 'off'' in fsuipc, but Not 'turbulence' suppress, the 747 goes stupid

FSX own turbulence weather the culprit? weird

and I did found some old topics, but nothing that would point me to your information now

thought I would post for others to find

bit of a waste of my 747x, almost

that I hadnt flown for years, for with my VA I fly PIC737, but with a new setup and a flight Beijing Amsterdam, I installed again an took me 20+ flights Schiphol-Dusseldorf to figure out why the 747X wasnt flying properly on its autopilot (unlike the FS9 version that flew rock solid)

also wind was no more than 24KT on FL150, so bit weird

;)

mt

[Pete Dowson]

with everything weather 'off'' in fsuipc, but Not 'turbulence' suppress, the 747 goes stupid

FSX own turbulence weather the culprit? weird

Hmmm .... FSUIPC4's own turbulence emulation only comes into operation if you have wind smoothing enabled. It was added because, unfortunately, FSX's own turbulence gets smoothed out by FSUIPC's smoothing otherwise. If you think you have everything in FSUIPC turned off then it cannot be FSUIPC's turbulence emulation.

Perhaps you need to let me see your FSUIPC4.INI file. If FSUIPC4 is doing anything at all you certainly must have something enabled.

In FS9 the wind smoothing in FSUIPC effectively removed all turbulence completely, so i thought that I would make things better for FSX by adding correct simulation. The algorithm follows correct small Gaussian pattern random changes in both wind speed and direction, proportional to both wind speed and degree of turbulence. There are two sources of turbulence -- cloud and wind, (clear air turbulence), both separately suppressible. FSX's cloud turbulence is actually more likely to upset aircraft than FSUIPC's, but its CAT seems hardly noticeable.

The algorithm used was tested by the real 747 pilot PMDG use to test their models, and he did confirm that FSUIPC's emulation was better than FSX's default.

If it is FSUIPC's turbulence which is doing this to you, you should see the wind indicator flickering slightly about its average direction, and the airspeed also flickering a bit. PMDG may smooth those out, but you can see it in the on -screen Shift+Z display. FSX's own simulation doesn't register on these things at all.

and I did found some old topics, but nothing that would point me to your information now

Really? There were some very long discussions exactly like the one you've started now. It went through quite a few iterations before fully working nicely to everyone's satisfaction.

bit of a waste of my 747x

Er, what does that mean?

If you want to see FSUIPC4's computations in action you can log them. If no smoothing/turbulence actions are being logged then you know it isn't that. To enable such logging do this:

Add to FSUIPC4.INI [General] section:

Debug=Please

LogExtras=768

Note that the log can get very big. I don't want to see it, but you can use it to see what is going on. Once you've set "Debug=Please" you can change the LogExtras number in the Logging TAB in FSUIPC options. For turbulence only change it to 256. For no extras logging change it to 0.

Regards

Pete