View Full Version : Wing Rocking on LNAV
12-17-2002, 12:49 AM
I've just recently purchased and installed the DF737. I'm really enjoying the challenge of flying this plane.
One thing I notice is an almost constant wing rocking on autopilot. Is this something I'm doing wrong? I noticed in the addendum to the manual that this is "scalable." I don't know what that means. Any help would be appreciated.
12-17-2002, 11:23 AM
It is caused by too much fuel, too much attempted speed and incorrect trim and climb rate for a given flight condition...I can porduce it anytime I want and eliminate it by slowing down and applying a corrected trim and a lower climb rate.
just put/change this in your .AIR file (Flight tuning):
pitch_stability = 1.2
roll_stability = 2.5
while you're in the .AIR file you maybe want to change this to:
fuel_flow_gain=0.003850 = for flightplanning like the real thing (TurbineEngineData)
pitch_scalar= 1.26 = for a better view when on final approach (Flaps.0)
I hope this helps....
01-22-2003, 10:17 PM
How do you get to this airfile?
And, Randall, did you try it and does it work?
I'm desperate to get this working right again.
01-22-2003, 10:35 PM
LAST EDITED ON Jan-22-03 AT 10:40PM (EST)[p]Adam,
If you have FS2002 Pro, the air file editor is included. The DF734 air file is locked for editing. You can save the air file to a different name and edit the copy. You can rename the orignal air file and stick the new one in it's place. (Please be careful.)
Note: In FSEdit, you cannot change the stabilities above 2.0
01-22-2003, 10:47 PM
I really thank you for the help. I've gotta ask you though...Did you have this wing rocking problem yourself?
And did you edit for it?
I'm definetly going to try your suggestion and I will be as careful as I can.
01-23-2003, 09:08 AM
Moved the setting to medium and pushed it no rocking...still can't figure out how the rocking suddenly arrived but if I can fix it you can too.
email me your phone number as I can't find where I put yours firstname.lastname@example.org
01-23-2003, 09:10 AM
Hi again Bill,
The AIR file you refer to - is it the 9Kb AIR file? If so it's all just gobble de gook to me. It's all just code or symbols or something. So am I supposed to rename this 9Kb file, then save a copy of the aircraft in FSEdit and make the changes? I'm a bit confused - it's in my nature!
Could you give me a little more specific directions?
I'll completely understand if you are not interested in doing so.
01-23-2003, 06:50 PM
Fire up FSEdit. Choose File Open. It will show you a list of aircraft that you have installed in FS2002, including all the DF737's you have installed. Choose one of those to edit. Now choose Save Copy As. FSEdit will show you the name it's going to save it as. It saves the WHOLE aircraft under a new name. You can then open this aircraft up in FSEdit and it will allow you to edit the flight dynamics. Make your changes, save it. Then you can try your changes out to see how they work. If they suit you, then replace the other air files with your new one.
I have not edited my DF737 in this manner. I have, on occasion, noticed a slight wing rock, but not everytime and not a huge amount. It is sensitive to speed, fuel load and trim.
01-23-2003, 09:24 PM
Thanks a bunch for the directions Bill. I'm trying a few other things doncarlos suggested first. Failing those, I'll give the editor a whirl. :-)
01-23-2003, 09:54 PM
Sounds good. Hopefully we can get it steady as she goes.
01-24-2003, 09:08 AM
Well I created a new DF with the airfile changes. I moved roll_stability from 1 to 2 and pitch_stability from 1 to 1.5. At first FS would not accept the aircraft citing an aircraft initialization failure. So, I copied the airfiles from the newly created DF file (as per your suggestion) into the original DF Flight One 737-400 file and then reloaded. This time it took. I loaded up DF and went for a flight. I was optimistic until I passed about FL230 and it started rocking away. At altitude it was madly rocking back and forth.
I'm giving DF a few more tries, then, to spare myself any more frustration, I'm removing it from FS. It's sad because I love the plane. It has worked beautifully in the past. After having tasted the true pleasure of the plane, it's too much of a compromise. I know this sounds a bit childish. Without a doubt, DF will be reloaded on my machine at some point in the future but for now I've had enough.
I have also not received any help from DreamFleet. I assumed as designers of the a/c that there might at least be some suggestions forthcoming. If the plane flies rock steady with LNAV engaged, something in the autopilot/FMC must be making it behave this way. I though it was winds or other environmental factors, but I have ruled these out as I've tried many flights with MS default weather - absolutely zero winds/clouds etc. I've tried different loadouts, different approaches to climb, speed and trim. In light of the fact that many people do not have a problem at all, I must conclude that something from my system/settings is/are causing the autopilot problem.
Again, thanks a lot for your help. I'll go back at it in the near future. I sincerely hope that DreamFleet creates a new 737 model and airfile specifically for FS2002. The plane is perfect for me - just the right size for the flights I like to do. Just the panel I want.
01-24-2003, 09:38 AM
Lots of people have this problem, so please be kind and don't ignore it!
01-24-2003, 01:37 PM
Line 8 in my post should read :...flies rock steady with LNAV DISENGAGED..."
01-24-2003, 01:38 PM
Maybe we can get some help if enough people have this problem and talk about it.
01-24-2003, 02:54 PM
I must admit I am stumped by this one.
The wing rocking suddenly appeared on my system approximately two weeks ago and I was able to fix it when I discovered for some reason i.e. me...had the fmc on hard capture in error. I then changed to soft...rocking gone and switched to medium capture and really pushed the climb and speed and still no rocking.
Yet Adam and I matched settings fuel loads climb rates etc etc etc and his will not go away.
There must be one of our experts who can figure this one out.
01-24-2003, 05:16 PM
In FS it's not possible to set a non-integer number as heading (345 degrees is possible, but not 345.33 degrees). In some situations, especially if the desired heading is in the middle between two "full" degrees - for example 345.5 - the aircraft will fly 345 degrees until the FMC-calculated course goes closer to 346, it will then turn to 346... then 345... 346... 345... 346... and so on. These little turns are the wing rocking effect you see. There's nothing you or we can do about it... sorry.
01-24-2003, 05:46 PM
Thankyou very much for replying. I understand exactly what you are saying, yet I fail to see how this could/would become a problem after it was not in the past - I mean that I have flown the same flights and not had the problem and now I do. Further, it happens with every flight now regardless of flight plan.
Please do not read my post as disagreeing with you. I really appreciate the fact that you, as a representative of DreamFleet, responded.
Will it be possible to overcome this in future releases of DF products, ie the new 737, if and when it is released?
Thank you Hans,
01-25-2003, 03:58 AM
Hmm..., in my opinion this has always been a problem but you won't notice the effect in most cases since if the desired heading isn't right in the middle between two degrees, there will be fewer heading corrections.
01-26-2003, 12:25 PM
01-27-2003, 03:50 AM
Glad to see you around here, again!
I thought you had fully dedicated to EW ;)
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