Sign in to follow this  
Roger Mazengarb

DG problem?

Recommended Posts

Has anyone noticed problems with the Directional Gyro in some of the Aircraft? When doing my pre-flight instrument check, I can't make sure the DG is aligned to the Magnetic Compass, yet the Autopilot 'Bug' on the DG moves fine!This problem seems to affect panels in various A/C. So far I have confirmed it on several C172 A/C from the library, as well as one Piper PA-28.I think this has something to do with file names as I have looked through all the PNL, PIT, AMP, etc, and can't find anything that would cause this. Adjustment knobs on all the other instruments seem to work fine - Altimeter, VOR/OBS, ADF, AI, etc. This problem seems isolated to the DG, but I can't find anything to cause it.Anyone else have the same problem? Anyone have a clue as to a fix?T.C.

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

G'day T.C.,Yes, the adjustment knob on the DG's doesn't work (no connection between the knob and the scale). The gyro's never experience apparent ( or real ) drift either (no matter what you have selected in the realism settings) ; they are constantly in agreement with the magnetic compass. All DG's behave as RMI's, as though there is a flux gate keeping the scale in constant alignment, never requiring resetting.Bug I'm afraid.Cheers,Roger @YSSY

Share this post


Link to post
Share on other sites

Roger, thanks for your reply. I have to say that this is a very 'odd' bug as it only affects some of the planes, without apparent cause in any of the text files that are used by the software to "define" the systems. I still believe it is a problem with file names, not a calculation or other similar bug in the software. However, I will be sure to note any findings for others to try.T.C.

Share this post


Link to post
Share on other sites

Roger,I recall that this question was once asked of Richard Harvey. I believe he stated that the only aircraft that had an adjustable DG was the Cessna (as in real life). The other aircraft supposedly modeled more sophisticated DGs that were self-adjusting.I do remember that the Cessna's DG in Fly!2K did drift and could be adjusted. I have not flown the Fly!2 version of the Cessna for some time, so I don't know if that was carried over or if it is one of those bugs that was never fixed.

Share this post


Link to post
Share on other sites

Hi all,Richard fixed the DG skyhawk bug in a patch : I can remember that when we made the PA28 we worked upon the skyhawk files as a guide but, unfortunally the DG fix was in the patch.pod !!!If you compare the sky main PNL file in the aircraft folder and the same main PNL file in the patch.pod (system folder) you'll see there's a tag (can't remenber now his signature) in the DG gauge section to remove (sort of automatic adjustment).If you remove (or add) this tag you'll have a working DG (drifted).CheersLaurentC (rotw)

Share this post


Link to post
Share on other sites

Laurent,It's the tag.Here is how the PNL entry should look like://////////////////////////////////////////////////// Directional gyro gauge////////////////////////////////////////////////// ==== GAUGE ENTRY ====gyro ==== BEGIN GAUGE ENTRY ==== ---- unique id ---- dgyr ---- x,y,xsize,ysize ---- 313 287 90 90 gyro yaw_ ---- overlay image ---- GYROOVER.PBM 2 2 ---- needle center x,y ---- 45 45 ---- angle range ---- 0.0 360.0 ---- bitmap needle ---- gyro ==== BEGIN BITMAP NEEDLE ==== ---- needle file ---- DGYRO.NDL ==== END BITMAP NEEDLE ==== ---- gyro correction knob ---- dgknob.pbg -4 76 15 94 ---- autopilot bug ---- apbug.pbg 2 2 _Bug ---- autopilot bug knob ---- skyhapkb.pbg 75 76 94 94 ---- bias tag ---- gyro ---- default cursor ---- mpfinger.csr ---- popup help ---- Directional Gyro ---- light flag ---- gage ---- light mask ---- skyhdgym.raw ==== END GAUGE ENTRY ====Regards,http://www.avsim.com/hangar/fly/dfdg/banneraa.jpg

Share this post


Link to post
Share on other sites

G'day Randall,I have seven aircraft that all have an incorrectly functioning DG. Cessna SkyhawkKodiaKSaharaPiper cubLong ezeCherokeeandMustang......not 100% sure of this but it isn't accepted practice to locate a compass in the centre of an instrument panel. Too much electical interference.All the above aircraft would have normal vacuum/electric gyro's in their DG,s The DG's would be set to the magnetic compass every 10-15 minutes to account for drift.In higher tech aircraft a flux gate is located away from all magnetic interference and the signal from this is used to drive the card (RMI).The 707 had one right out at the wing tip, even used aluminium screws in the access panel!!It looks like Laurent and Alex have a fix for this .Cheers,Roger @YSSY

Share this post


Link to post
Share on other sites

G'day Alex,Very strange; Checked out the TRI Flyhawk and the DG adjustment knob worked :-jumpy but all the repaints don't. :-( Nor do any panels that may have borrowed the DG from the original TRI aircraft.Whilst the repaints do have their own main pnl files, the bias tag and all the coding below it appears to be included.Making them the default startup aircraft didn't make any difference either.Alex I just found the patch.pod (system folder) released by TRI. They did remove the bias tag.I removed the bias tag from the repaints pnl file and now they also have a functioning adjuster knob. I'm off now to see if drift works. I now see why the patch only fixes the Tri Flyhawk as the repaints had renamed panel files.Cheers,Roger @YSSY

Share this post


Link to post
Share on other sites

G'day T.C.,All aircraft (other than the TRI Flyhawk) that have a DG are affected. Follow the thread; luckily we have some great guru's on the forum. I'm a happy camper! :-)Cheers,Roger @YSSY

Share this post


Link to post
Share on other sites

G'day Randall,Thank Laurent for pointing out the fix! The fix (for the TRI Flyhawk)is actually in the patch.pod in the system folder (that's well hidden :-) ) For the other aircraft it is simply a matter of applying the same reasoning to their panel files.I've corrected the front pnl file for Cessna Skyhawk (TRI)Cessna milleniumPiper pa 28 CherokeeMalibu/SaharaNavajo/KodiakLong EZIf anyone wants to do this for yourself it is very easy. All you have to do is 1. extract the front panel *.pnl file from the pod (use podview in tools folder)2. open the file in wordpad and delete the tag (only 2 lines of code)in the directional gyro definition section of the *.pnl file.3. save the modified *.pnl file to the DATA folder in FlyII.You must also of course have SearchPodFilesFirst=0 set in the Fly.ini file in the SYSTEMS folder in FlyII.If you wish to revert to the original TRI panels simply delete the modified *.pnl files from the DATA folder. Now they all have DG's that can be set and drift.All this begs the question - Why did TRI (Rich?) nobble all the DG's in the first place?? Maybe a beta tester may remember something and can shed some light on this?Cheers,Roger @YSSY

Share this post


Link to post
Share on other sites

Roger,I was a part of the beta team (working in different areas) and I believe my previous statement to be accurate. Rich had made the statement to another member of the team on the DG issue that only the Cessna required reset capability - considering your expertise in this area, you must be right and they were wrong.Here's my guess on what happened:1. Somehow they got the idea that all of the DGs were self-adjusting except for the Cessna.2. Going on that premise, they added the tag in Fly!2 to turn off that capability on the more advanced aircraft.3. They eventually discovered they had not only killed that adjustment for those aircraft, but knocked it off for the Cessna.4. Shortly before his death, Rich or someone discovered the Cessna issue and corrected it it one of the last patches.I would bet if we go through some of the patch documentation, we'll see it mentioned.

Share this post


Link to post
Share on other sites

Randy,I went back to the Fly! Beta forum and found one message that mentions a fix but I couldn't find the thread itself. Maybe it was in the old Beta forum to which we no longer have access... :-(Anyway, it's nice to know that it has been fixed.Take care,http://www.avsim.com/hangar/fly/dfdg/banneraa.jpg

Share this post


Link to post
Share on other sites

G'day Randall, > considering your expertise in this area, you must be right and they were wrong.:-eek :-eekNever concede an issue due to position. I've made more mistakes than you've had Sunday dinners. :-)This could be my biggest blunder yet :-lolI'm going to a BBQ at work on Wednesday and I'll quiz the experts. Cheers,Roger @YSSY

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this