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pilotito84
Joined: 11 Sep 2017 Posts: 15 Location: Tucson, AZ
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Posted: Wed Oct 17, 2018 6:18 pm Post subject: Pitch Oscillations and Uncoordinated flight |
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I have a problem with Pitch Oscillations during cruise flights. On my climb outs everything looks normal until it reaches level off altitudes. For some reason the aircraft starts oscillating up and down around my altitude but the AP never seems to lock it and trim to hold that. It just keeps going up and down as much as +/- 1000 FPM. I have already reset the AP to defaults with no change. Also my aircraft never seems to maintain turn coordination during turns or even on straight and level flight neither on manual or AP. Any suggestions???
P.S. I took a picture and video but I didn't know how to load it
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MichaelYSSY
Joined: 06 Jan 2015 Posts: 645 Location: Sydney - Australia
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Posted: Thu Oct 18, 2018 1:21 am Post subject: |
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Hello there
Sorry didn't catch your name
What version of SA are you using?
P3D V?
FSUIPC V?
AIRCRAFT MODEL?
Could be a lot of things
Latest versions that I'm using seem stable at cruise alt level off
Cheers
Michael _________________ SSTD 737, SA 737 v1.961
P3D 4.5 FSUIPC 5.152 |
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thomas747400
Joined: 14 Feb 2016 Posts: 96 Location: Perth, Western Australia
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Posted: Thu Oct 18, 2018 8:10 am Post subject: |
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Hi Pilotito84
I fly the T777 and I experience the exact same issues you are having.
As for the oscillations, I am tinkering with the autopilot settings, I have had some promising signs with changing the Altitude Hold Accel Damping from -900 to -1200 but I have to do some more testing.
I am trying to identify the turn coordination issue myself perhaps we can compare some parameters:
P3D Autorudder >Off
Sim A PFC/ FBW Enabled > Off
TAC Enabled / Yaw Damper > On
Do I need to activate the Yaw Damper in the T7? I can't find a switch for that on the Overhead Panel.
I only have coordination issues at low altiudes < 5000ft. Above that, it is usually pretty good.
Thomas |
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pilotito84
Joined: 11 Sep 2017 Posts: 15 Location: Tucson, AZ
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Posted: Thu Oct 18, 2018 8:49 am Post subject: |
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Hi Michael, sorry about that i forgot to mention my specs. Im using P3D v4,
FSUIPC 5, and flying the T7 model. As for the SA i am using 1.9.
Francisco
Last edited by pilotito84 on Thu Oct 18, 2018 6:44 pm; edited 1 time in total |
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pilotito84
Joined: 11 Sep 2017 Posts: 15 Location: Tucson, AZ
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Posted: Thu Oct 18, 2018 8:54 am Post subject: |
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Hello Thomas,
I’ll be more than happy to work with you in trying to figure out the problem. I have the same settings as you, and have tried it with FBW (even though the manual says that is not modeled) and yaw damper enabled with the same results.
As for the turn coordination i have the same symptoms as you. At lower altitudes is definitely more noticeable with the trim indicator deflecting almost completely. Up in higher altitudes it doesn’t deflect as much but deflects enough to be noticed.
Francisco |
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kand
Joined: 03 Feb 2016 Posts: 187 Location: Buckinghamshire, UK
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Posted: Fri Oct 19, 2018 1:47 am Post subject: |
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Does this occur in zero weather?
I had this with the 777, my problem turned out to be the turbulence setting, I disabled the P3d setting and also reduced the numbers in Activesky, my porpoising stopped after that. |
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thomas747400
Joined: 14 Feb 2016 Posts: 96 Location: Perth, Western Australia
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Posted: Fri Oct 19, 2018 7:20 am Post subject: |
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Hi kand,
I have experienced these issues since upgrading to v1.9. Prior to that it was fine. I will do some testing in clear and wind free weather.
Cheers
Thomas |
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Fred
Joined: 15 Mar 2005 Posts: 150
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Posted: Fri Oct 19, 2018 12:20 pm Post subject: |
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Hi All
Since upgrading to 1.91 I am also having problems with pitch oscillations in level flight and in VNAV/LVL CHG ascents/descents (as described in the related previous thread).
A combination of the following here has seemed to help:
(1) ALT Hold Accel Damping -700 -> -1200
(2) In the aircraft.cfg file:
[flight_tuning]
elevator_effectiveness = 1.0 -> 0.7
aileron_effectiveness = 1.1 -> 0.7
rudder_effectiveness = 1.3 -> 1.1
In the couple of fair weather flight I have flown I have found this combination has eliminated the pitch oscillations in level flight. Also, VNAV descents now work smoothly. VNAV ascents have been improved significantly however there is still an issue with the first 30 seconds or so. In VNAV ascent the rate of climb initially rises slightly but then quickly swings into a negative rate, then followed by oscillations between positive/negative rate which gradually stabilize within 30-45 seconds. (Without the above mods those oscillations would never stabilize.)
I will be doing more testing on all this later today.
Using P3Dv1 and the SimA 737.
Fred K |
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Tankleader
Joined: 23 Dec 2016 Posts: 29
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Posted: Fri Oct 19, 2018 3:24 pm Post subject: Pitch Oscillations and Uncoordinated Flight |
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Hello All,
I am having the same issue. It seems to start randomly during the flight and ends with an uncontrollable aircraft.
Sim-Avionics Server= 1.90
P3D V=3.4.18.19475
FSUIPC V=4.974
WideServer= 7.1.5.1
AIRCRAFT MODEL= Ver 1.9 B777, FSX-Sim-Avionics-B777
When this occurs I select Alt-Tab and check to see what the server is doing. I've noticed that the Flt Data Rate 16 FPS and the A/P Rate 10 or 11 FPS drop to 1 FPS resulting in the lag causing the system to chase itself. This is just my observation in trying to figure out in what is happening. This issue has manifested itself in all 3 of my flights since I updated the other day.
Thanks
Andreas J Elesky |
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MichaelYSSY
Joined: 06 Jan 2015 Posts: 645 Location: Sydney - Australia
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Posted: Fri Oct 19, 2018 4:32 pm Post subject: |
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Hi guys
Sorry to hear. I have the B737
Not getting this problem with 1.91 but it did happen with a previous SA version 1.8?
It was sorted out when it happened and I cant remember what the cause was? Something reminds me of YAW Damper issue? but AP frame rates could have been involved too.
Im sure Mark will sort it out quickly.
Oh, and Welcome to the Forum Francisco, sorry couldn't help you out on this one seems that B737 and B777 have different systems
Cheers
Michael _________________ SSTD 737, SA 737 v1.961
P3D 4.5 FSUIPC 5.152 |
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Tankleader
Joined: 23 Dec 2016 Posts: 29
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Posted: Fri Oct 19, 2018 4:42 pm Post subject: |
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MichaelYSSY wrote: | Hi guys
Not getting this problem with 1.91 but it did happen with a previous SA version 1.8?
Cheers
Michael |
Where is everyone getting 1.91 from? I just downloaded 1.9 from the link on the announcement page.
Thanks
Andy |
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Fred
Joined: 15 Mar 2005 Posts: 150
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Posted: Fri Oct 19, 2018 4:43 pm Post subject: |
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Fred wrote: | Hi All
Since upgrading to 1.91 I am also having problems with pitch oscillations in level flight and in VNAV/LVL CHG ascents/descents (as described in the related previous thread).
A combination of the following here has seemed to help:
(1) ALT Hold Accel Damping -700 -> -1200
(2) In the aircraft.cfg file:
[flight_tuning]
elevator_effectiveness = 1.0 -> 0.7
aileron_effectiveness = 1.1 -> 0.7
rudder_effectiveness = 1.3 -> 1.1
In the couple of fair weather flight I have flown I have found this combination has eliminated the pitch oscillations in level flight. Also, VNAV descents now work smoothly. VNAV ascents have been improved significantly however there is still an issue with the first 30 seconds or so. In VNAV ascent the rate of climb initially rises slightly but then quickly swings into a negative rate, then followed by oscillations between positive/negative rate which gradually stabilize within 30-45 seconds. (Without the above mods those oscillations would never stabilize.)
I will be doing more testing on all this later today.
Using P3Dv1 and the SimA 737.
Fred K |
Spent the entire afternoon investigating further tuning doing flight level changes......
In addition to the above I have changed the following in the SimA A/P tuning section:
[FLCH]
Accel Damping: 0.7 -> 0.1
Sensitivity Reduction: 6 -> 9
Desc Aggression: 5 -> 3
All of the changes I have made are in the direction of decreasing sensitivities and increasing damping. I systematically titrated to each of those values.
The results are that the oscillations are completely eliminated in level flight and the FLTCHG performance is very smooth and acceptable (both VNAV and LVL), albeit perhaps a little bit slow to initiate, but I can live with that.
If this sticks I am happy.
Fred K |
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pilotito84
Joined: 11 Sep 2017 Posts: 15 Location: Tucson, AZ
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Posted: Fri Oct 19, 2018 8:36 pm Post subject: |
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Thank you all for jumping into this thread and taking the time trying to help me figure it out. So far, I have also reduced the weather to zero and everything was fine up to the level off, it then just started doing its thing again. Also still no luck with the out of turn coordination issue as well.
Thank yo for the welcoming message MichaelYSSY  |
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kand
Joined: 03 Feb 2016 Posts: 187 Location: Buckinghamshire, UK
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Posted: Sat Oct 20, 2018 3:15 am Post subject: |
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Tankleader wrote: | MichaelYSSY wrote: | Hi guys
Not getting this problem with 1.91 but it did happen with a previous SA version 1.8?
Cheers
Michael |
Where is everyone getting 1.91 from? I just downloaded 1.9 from the link on the announcement page.
Thanks
Andy |
On the download page of the simA website, 1.91 latest official release |
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Tankleader
Joined: 23 Dec 2016 Posts: 29
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Posted: Sat Oct 20, 2018 11:20 am Post subject: |
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kand wrote: |
On the download page of the simA website, 1.91 latest official release |
Thanks, I didn't think to check there.
Thanks
Andy |
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