Re: [Flightgear-devel] autopilots, adverse aileron yaw and jsbsim questions
is as solid as a rock with the default turbulence all the way down the glide slope. With the turbulence zero, both behave the same. The SenecaII wing rock with light turbulence appears to result from a very exaggerated adverse aileron yaw. So I did the same experiment with the c172p and pa28-140 which both use the kap140. With the default turbulence, the c172p oscillates so bad that you cannot complete the approach with the LOC needle going full stop to full stop near the runway. The pa28-161 (also yasim) is as solid as a rock all the way down the glide slope with light to moderate turbulence. Can someone tell me what turning turbulence on in FlightGear does (apart from the obvious)? Which properties are set to model turbulence, which are then presumably passed to the FDM? Jon - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] autopilots, adverse aileron yaw and jsbsim questions
On 07/10/2007, Jon S. Berndt [EMAIL PROTECTED] wrote: I looked at the configuration file for the Seneca II in flightgear cvs. It appears to me (at least given the quick glance I took) that adverse aileron yaw (Cnda) is turned off - the data is all zeros. I'm not sure about the exact derivatives, but the real PA-28 and the 172 experience negligible adverse yaw in level cruise at bank angles under 20-30 degrees -- you can fly them with your feet flat on the floor and the slip-skid ball barely moves. In both, I think, it's the use of differential aileron deflections that does the trick. All the best, David - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Flight Gear runtime failure
On 10/8/07, James Reinsberg [EMAIL PROTECTED] wrote: [EMAIL PROTECTED]:~/applications/FlightGear/source$ fgfs *** glibc detected *** fgfs: free(): invalid pointer: 0x08746e10 *** === Backtrace: = /lib/tls/i686/cmov/libc.so.6[0xb74037cd] /lib/tls/i686/cmov/libc.so.6(cfree+0x90)[0xb7406e30] /usr/lib/libstdc++.so.6(_ZdlPv+0x21)[0xb759ed11] /usr/local/lib/libosg.so.25(_ZN3osg16DrawArrayLengthsD0Ev+0x37)[0xb7aae767] Let me guess: ati driver? -- Csaba - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] win32 0.9.11 latest binary, where?
2007/10/6, Thomas [EMAIL PROTECTED]: plib (0.9.11pre) version: http://www.rato.us/flightgear/builds/plib/20071005plibexe.zip Just in case you'd like to try that version: http://www.rato.us/flightgear/builds/osg/20071005osgexe.zip Thanks Thomas for your exe's! But I got this, after loading scenery and setup systems: Model Author: Unknown Creation Date: 2002-01-01 Version: $Id: c172p.xml,v 1.17 2006-03-13 15:27:14 Description: Cessna C-172 Unknown top level section: wxradar Fatal error: Detected an internal inconsistency in the inst system specification file. See earlier errors for details. May be I need to update some files in data folder? -- --- WBR, Vadym. - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] autopilots, adverse aileron yaw and jsbsim questions
On Monday 08 October 2007 02:17, dave perry wrote: While optimizing the aitopilot config files for the Century IIB and III autopilots for the pa24 and the Altimatic IIIc for the SenecaII, a significant difference between the values of parameters (gains in particular) that give non oscillatory behavior in yasim and jsbsim became very apparent. I had to completely turn off turbulence to get stability without significant overshoot in SenecaII/Systems/ALTIMATICIII.xml. With the values submitted to cvs, the Seneca still has a wing rock in LOC REV and LOC modes with the default weather that has some turbulence. The pa24 with the same values is as solid as a rock with the default turbulence all the way down the glide slope. With the turbulence zero, both behave the same. The SenecaII wing rock with light turbulence appears to result from a very exaggerated adverse aileron yaw. So I did the same experiment with the c172p and pa28-140 which both use the kap140. With the default turbulence, the c172p oscillates so bad that you cannot complete the approach with the LOC needle going full stop to full stop near the runway. The pa28-161 (also yasim) is as solid as a rock all the way down the glide slope with light to moderate turbulence. If you watch the oscillation for either jsbsim model, you should note that when the yoke is rotating counter clockwise, the nose is yawing right and then finally swings back left, as would be expected with extreme adverse aileron yaw. Most high performance AC show very little AAY except in significant slow flight. I would not expect that small aileron deflections should move the nose counter to the roll in a SenecaII or pa24. Two questions: 1. Have others noticed this difference between jsbsim and yasim? 2. Can this adverse aileron yaw be toned down in jsbsim? Regards, Dave Perry Is auto-coordination enabled? I don't think this is effective for YASim aircraft but it may be complicating things on JSBSim aircraft. Also, are you getting the same frame-rates with both aircraft? Last time I ran FG I found that the autopilot PID controllers ran at the frame rate and not at the Ts rate specified in the controller definitions, which could make them unstable outside a fairly narrow range of fps. LeeE - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] autopilots, adverse aileron yaw and jsbsim questions
Is auto-coordination enabled? I don't think this is effective for YASim aircraft but it may be complicating things on JSBSim aircraft. Also, are you getting the same frame-rates with both aircraft? Last time I ran FG I found that the autopilot PID controllers ran at the frame rate and not at the Ts rate specified in the controller definitions, which could make them unstable outside a fairly narrow range of fps. LeeE I'm also taking a look at turbulence modeling in JSBSim. That's one area we have not paid a lot of attention and testing to. Jon - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] autopilots, adverse aileron yaw and jsbsim questions
leee wrote: On Monday 08 October 2007 02:17, dave perry wrote: While optimizing the aitopilot config files for the Century IIB and III autopilots for the pa24 and the Altimatic IIIc for the SenecaII, a significant difference between the values of parameters (gains in particular) that give non oscillatory behavior in yasim and jsbsim became very apparent. I had to completely turn off turbulence to get stability without significant overshoot in SenecaII/Systems/ALTIMATICIII.xml. With the values submitted to cvs, the Seneca still has a wing rock in LOC REV and LOC modes with the default weather that has some turbulence. The pa24 with the same values is as solid as a rock with the default turbulence all the way down the glide slope. With the turbulence zero, both behave the same. The SenecaII wing rock with light turbulence appears to result from a very exaggerated adverse aileron yaw. So I did the same experiment with the c172p and pa28-140 which both use the kap140. With the default turbulence, the c172p oscillates so bad that you cannot complete the approach with the LOC needle going full stop to full stop near the runway. The pa28-161 (also yasim) is as solid as a rock all the way down the glide slope with light to moderate turbulence. If you watch the oscillation for either jsbsim model, you should note that when the yoke is rotating counter clockwise, the nose is yawing right and then finally swings back left, as would be expected with extreme adverse aileron yaw. Most high performance AC show very little AAY except in significant slow flight. I would not expect that small aileron deflections should move the nose counter to the roll in a SenecaII or pa24. Two questions: 1. Have others noticed this difference between jsbsim and yasim? 2. Can this adverse aileron yaw be toned down in jsbsim? Regards, Dave Perry Is auto-coordination enabled? I don't think this is effective for YASim aircraft but it may be complicating things on JSBSim aircraft. Also, are you getting the same frame-rates with both aircraft? Last time I ran FG I found that the autopilot PID controllers ran at the frame rate and not at the Ts rate specified in the controller definitions, which could make them unstable outside a fairly narrow range of fps. I have the frame rate throttled to 25 hz as that is achievable with my setup and both AC. I have tried turning on auto coordination. This helps a little. Also, I included a yaw damper in the autopilot config file for the SenecaII. This helps most of the time but can also add to the problem. Toggle for the yaw damper is a SenecaII menu item in the patches I sent to Andy. Here are the switches from my last test from fgrun. /usr/local/FlightGear-plib/data/bin/fgfs --fg-root=/usr/local/FlightGear-0.9/data --fg-scenery=/usr/local/FlightGear-0.9/data/Scenery:/usr/local/FlightGear-0.9/Scenery-0.9.10 --airport-id=KSFO --aircraft=SenecaII-jsbsim --control=joystick --disable-random-objects --disable-ai-models [EMAIL PROTECTED] --turbulence=0.49 --geometry=1680x1050 --visibility-miles=15 --bpp=24 --fov=65 --timeofday=dusk --nmea=socket,out,5,localhost,5500,udp --prop:/sim/frame-rate-throttle-hz=25 In this test, I turned the turbulence up to 0.49. With this value, the pa24 bounces around a lot and you see the impact of what seems to be thermals and wind shear, but the Century III autopilot flies right down the LOC/GS past the inner marker for RW28R at KSFO. The turbulence means I am constantly adjusting the throttle, but the AP does a good job for all else. LOC and GS stay very nearly centered. With the SenecaII and 0.49 turbulence, it is hardly controllable without the AP, and definitely not controllable with the AP. I think Jon B. is onto something by asking how turbulence is implemented in the various fdms. Thanks for the ideas, Dave - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] win32 0.9.11 latest binary, where?
Vadym Kukhtin wrote: 2007/10/6, Thomas [EMAIL PROTECTED] mailto:[EMAIL PROTECTED]: plib (0.9.11pre) version: http://www.rato.us/flightgear/builds/plib/20071005plibexe.zip http://www.rato.us/flightgear/builds/plib/20071005plibexe.zip Just in case you'd like to try that version: http://www.rato.us/flightgear/builds/osg/20071005osgexe.zip http://www.rato.us/flightgear/builds/osg/20071005osgexe.zip Thanks Thomas for your exe's! But I got this, after loading scenery and setup systems: Model Author: Unknown Creation Date: 2002-01-01 Version: $Id: c172p.xml,v 1.17 2006-03-13 15:27:14 Description: Cessna C-172 Unknown top level section: wxradar Fatal error: Detected an internal inconsistency in the inst system specification file. See earlier errors for details. May be I need to update some files in data folder? -- --- WBR, Vadym. If you started from a 0.9.10 installation, yes, you must update your data from CVS. -Reagan - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] oil platform...
Hi, A video of Sea Kings starting and landing an a ship: http://pilotservices.streamlinenettrial.co.uk/videos/*Sea_Kings_on_Deck.wmv* this video is not of very good quality, but it's more than worth to see. Maik Robert Black schrieb am 08.10.2007 03:03: On Wednesday 03 October 2007 19:05, SydSandy wrote: Log Message: Oil platform for helicopter practice I was thinking about this and thought of a ship with a helo deck which could be anything from a yacht to cargo ships and ships in the Niimitz Strike Force or a Coast Guard type and then I thought of an Amphibious assault type as they have a large deck and support helo's, Harriers and the Osprey. http://en.wikipedia.org/wiki/Amphibious_assault_ship#List_of_amphibious_assault_ship_types Robert - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] win32 0.9.11 latest binary, where?
Reagan Thomas ha scritto: Vadym Kukhtin wrote: 2007/10/6, Thomas [EMAIL PROTECTED] mailto:[EMAIL PROTECTED]: plib (0.9.11pre) version: http://www.rato.us/flightgear/builds/plib/20071005plibexe.zip http://www.rato.us/flightgear/builds/plib/20071005plibexe.zip Just in case you'd like to try that version: http://www.rato.us/flightgear/builds/osg/20071005osgexe.zip http://www.rato.us/flightgear/builds/osg/20071005osgexe.zip Thanks Thomas for your exe's! But I got this, after loading scenery and setup systems: Model Author: Unknown Creation Date: 2002-01-01 Version: $Id: c172p.xml,v 1.17 2006-03-13 15:27:14 Description: Cessna C-172 Unknown top level section: wxradar Fatal error: Detected an internal inconsistency in the inst system specification file. See earlier errors for details. May be I need to update some files in data folder? -- --- WBR, Vadym. If you started from a 0.9.10 installation, yes, you must update your data from CVS. -Reagan I get the same error msg using Torsten's PA34-200T. I am using Data files dated 16-05-2007, which is ver.0.9.11 (and works with a previous pre.0.9.11) I downloaded some time ago. Roberto - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] win32 0.9.11 latest binary, where?
Roberto Inzerillo wrote: Reagan Thomas ha scritto: Vadym Kukhtin wrote: 2007/10/6, Thomas [EMAIL PROTECTED] mailto:[EMAIL PROTECTED]: plib (0.9.11pre) version: http://www.rato.us/flightgear/builds/plib/20071005plibexe.zip http://www.rato.us/flightgear/builds/plib/20071005plibexe.zip Just in case you'd like to try that version: http://www.rato.us/flightgear/builds/osg/20071005osgexe.zip http://www.rato.us/flightgear/builds/osg/20071005osgexe.zip Thanks Thomas for your exe's! But I got this, after loading scenery and setup systems: Model Author: Unknown Creation Date: 2002-01-01 Version: $Id: c172p.xml,v 1.17 2006-03-13 15:27:14 Description: Cessna C-172 Unknown top level section: wxradar Fatal error: Detected an internal inconsistency in the inst system specification file. See earlier errors for details. May be I need to update some files in data folder? -- --- WBR, Vadym. If you started from a 0.9.10 installation, yes, you must update your data from CVS. -Reagan I get the same error msg using Torsten's PA34-200T. I am using Data files dated 16-05-2007, which is ver.0.9.11 (and works with a previous pre.0.9.11) I downloaded some time ago. Roberto The source code and aircraft files were changed on or around June 24 2007 to change the wxradar tag to radar. Your data files will need to be newer than that to run a current binary. - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
[Flightgear-devel] Vulcan Livery Patch
Hi All, Please find below a patch for the vulcan to fix the liveries on plib. I'd be grateful if someone would commit it to CVS. Thanks -Stuart Index: vulcanb2-set.xml === RCS file: /var/cvs/FlightGear-0.9/data/Aircraft/vulcanb2/vulcanb2-set.xml,v retrieving revision 1.8 diff -u -r1.8 vulcanb2-set.xml --- vulcanb2-set.xml13 Jul 2007 20:30:20 -1.8 +++ vulcanb2-set.xml7 Oct 2007 18:41:48 - @@ -24,9 +24,11 @@ model path archive=yAircraft/vulcanb2/Models/vulcanb2.xml/path - vulcanb2 -textureskin.rgb/texture - /vulcanb2 + livery +material + textureXM597.rgb/texture +/material + /livery offsets x-m-15.0/x-m y-m0.0/y-m @@ -36,7 +38,6 @@ !-- Initial variant and texture. Controlled by aircraft dialog. -- variantXM597/variant -textureXM597.rgb/texture !-- Initial armament. Controlled by aircraft dialog -- armamentBlackBuck6/armament Index: vulcanb2.xml === RCS file: /var/cvs/FlightGear-0.9/data/Aircraft/vulcanb2/vulcanb2.xml,v retrieving revision 1.3 diff -u -r1.3 vulcanb2.xml --- vulcanb2.xml17 Apr 2007 21:10:12 -1.3 +++ vulcanb2.xml4 Oct 2007 20:34:36 - @@ -76,6 +76,14 @@ y 0.00 /y z -29.97 /z /location + pointmass name=dummy + weight unit=LBS1/weight + location name=dumm2 unit=IN + x 659.38/x + y 0.0/y + z -29.97/z + /location + /pointmass /mass_balance ground_reactions Index: Dialogs/config.xml === RCS file: /var/cvs/FlightGear-0.9/data/Aircraft/vulcanb2/Dialogs/config.xml,v retrieving revision 1.2 diff -u -r1.2 config.xml --- Dialogs/config.xml7 Jan 2007 18:04:31 -1.2 +++ Dialogs/config.xml5 Aug 2007 17:59:03 - @@ -60,7 +60,7 @@ pref-width4/pref-width /empty text - labelArmament /label + labelArmament/label /text combo property/sim/armament/property Index: Models/vulcanb2.ac === RCS file: /var/cvs/FlightGear-0.9/data/Aircraft/vulcanb2/Models/vulcanb2.ac,v retrieving revision 1.4 diff -u -r1.4 vulcanb2.ac --- Models/vulcanb2.ac31 Oct 2006 20:55:25 -1.4 +++ Models/vulcanb2.ac5 Aug 2007 18:39:42 - @@ -28,7 +28,7 @@ name LeftGearHinge data 4 Cube -texture //XM597.rgb +texture XM597.rgb texrep 1 1 crease 30 numvert 8 @@ -88,7 +88,7 @@ name BrakeLowerRight data 8 Cube.004 -texture //XM597.rgb +texture XM597.rgb texrep 1 1 crease 30 numvert 24 @@ -248,7 +248,7 @@ name RightGearDoorRear data 12 Door 4 H.001 -texture //XM597.rgb +texture XM597.rgb texrep 1 1 crease 30 numvert 8 @@ -308,7 +308,7 @@ name Cylinder data 12 Cylinder.001 -texture //XM597.rgb +texture XM597.rgb texrep 1 1 crease 30 numvert 33 @@ -559,7 +559,7 @@ name LeftGearPistonHead data 18 Gear 2 strut H.005 -texture //XM597.rgb +texture XM597.rgb texrep 1 1 crease 30 numvert 16 @@ -5152,7 +5152,7 @@ name RightGearWheel1 data 12 Cylinder.004 -texture //XM597.rgb +texture XM597.rgb texrep 1 1 crease 30 numvert 264 @@ -7858,7 +7858,7 @@ name RightGearWheel2 data 12 Cylinder.003 -texture //XM597.rgb +texture XM597.rgb texrep 1 1 crease 30 numvert 264 @@ -10564,7 +10564,7 @@ name OuterElevonLeft data 8 Mesh.022 -texture //XM597.rgb +texture XM597.rgb texrep 1 1 crease 30 numvert 13 @@ -10679,7 +10679,7 @@ name Nacelle.004 data 15 Nacelle 1 H.005 -texture //XM597.rgb +texture XM597.rgb texrep 1 1 crease 30 numvert 66 @@ -11283,7 +11283,7 @@ name Rudder data 8 Mesh.017 -texture //XM597.rgb +texture XM597.rgb texrep 1 1 crease 30 numvert 12 @@ -11390,7 +11390,7 @@ name RightGearStrut data 8 Cylinder -texture //XM597.rgb +texture XM597.rgb texrep 1 1 crease 30 numvert 48 @@ -11616,7 +11616,7 @@ name RightGearHinge data 8 Cube.001 -texture //XM597.rgb +texture XM597.rgb texrep 1 1 crease 30 numvert 8 @@ -11676,7 +11676,7 @@ name RightGearDoor data 8 Door 3 H -texture //XM597.rgb +texture XM597.rgb texrep 1 1 crease 30 numvert 8 @@ -11736,7 +11736,7 @@ name LeftGearBogey data 18 Gear 4 strut H.003 -texture //XM597.rgb +texture XM597.rgb texrep 1 1 crease 30 numvert 14 @@ -11874,7 +11874,7 @@ name InsideCanopy data 10 Sphere.004 -texture //XM597.rgb +texture XM597.rgb texrep 1 1 crease 30 numvert 97 @@ -12629,7 +12629,7 @@ name ChuteDoor_1 data 10 Sphere.001 -texture //XM597.rgb +texture XM597.rgb texrep 1 1 crease 30 numvert 158 @@ -13781,7 +13781,7 @@ name Nacelle.003 data 15 Nacelle 1 H.004 -texture //XM597.rgb +texture XM597.rgb texrep 1 1 crease 30 numvert 66 @@ -14385,7 +14385,7 @@ name Nacelle data 15 Nacelle 1 H.006 -texture //XM597.rgb +texture XM597.rgb texrep 1 1 crease 30 numvert 66 @@
Re: [Flightgear-devel] autopilots, adverse aileron yaw and jsbsim questions
I think Jon B. is onto something by asking how turbulence is implemented in the various fdms. Thanks for the ideas, Dave Does anyone know what typical values are for these two properties: /environment/turbulence/magnitude-norm /environment/turbulence/rate-hz The fact that the first property is named magnitude-norm (emphasis on the *norm*) makes me suspect that the turbulence goes from _1 to +1. But, that wouldn't do much for turbulence. And, is that 1 ft/sec? Or is it the value of the turbulence in ft/sec? Jon - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] autopilots, adverse aileron yaw and jsbsim questions
The SenecaII wing rock with light turbulence appears to result from a very exaggerated adverse aileron yaw. So I did the same experiment with the c172p and pa28-140 which both use the kap140. With the default turbulence, the c172p oscillates so bad that you cannot complete the approach with the LOC needle going full stop to full stop near the runway. The pa28-161 (also yasim) is as solid as a rock all the way down the glide slope with light to moderate turbulence. Another thing I'd like to see is a test from steady state that reproduces the worst of the problem with no turbulence. That way I can set up a similar test in JSBSim by itself and script a set of maneuvers that duplicates the problem. Jon - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] autopilots, adverse aileron yaw and jsbsim questions
On Monday 08 October 2007 02:17, dave perry wrote: The SenecaII wing rock with light turbulence appears to result from a very exaggerated adverse aileron yaw. So I did the same experiment with the c172p and pa28-140 I agree that they both exhibit unrealistically bad handing characteristics. The 182 and 182rg were also quite nasty, until I brutally hacked the configuration to reduce it. One slight quibble: I'm not sure I would characterize all of the problem as adverse yaw. In addition to whatever adverse yaw problems there were, I noticed an excessive amount of slip-roll coupling. That is, any slip (due to ailerons or rudder or otherwise) produced a tremendous amount of rolling moment. This is a recipe for some bad Dutch Roll behavior, which is pretty much what I observed. We agree that aileron deflection was an easy way to set off this bad behavior, but I'm not sure that adverse yaw is the whole story. Somebody needs to look at all the parameters from top to bottom. which both use the kap140. I don't think that's the primary issue ... although there might be a /secondary/ issue with the kap140 being more vulnerable to bad handling characteristics than some other autopilots are; I don't know. I recommend fixing the flight dynamics first, and only then looking to see what secondary issues might exist. Other oddity in the flight dynamics is: much too much rolling moment due to changes in engine power setting. I would have tried to fix this, but I didn't see any parameter to control this in the configuration file. I know there is some irreducible rotational drag from the propeller, and this rightly belongs in the engine/prop configuration ... but there are other things such as asymmetric wing-root incidence that are used to counteract it ... I didn't do an exhaustive search, but I didn't see that anywhere. There are many other oddities, such as fuel never being consumed from fuel tanks, effective mixture not being sensitive to altitude, EGT reading high and insensitive to mixture, etc. etc. - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] autopilots, adverse aileron yaw and jsbsim questions
On 08/10/2007, Jon S. Berndt [EMAIL PROTECTED] wrote: Does anyone know what typical values are for these two properties: /environment/turbulence/magnitude-norm /environment/turbulence/rate-hz The fact that the first property is named magnitude-norm (emphasis on the *norm*) makes me suspect that the turbulence goes from _1 to +1. But, that wouldn't do much for turbulence. And, is that 1 ft/sec? Or is it the value of the turbulence in ft/sec? I helped implement this with Tony a few years ago. As I recall, the value was from 0 to 1, where 0 represents no turbulence, and 1 represents the most severe turbulence that we model. You couldn't represent turbulence simply in feet/second, because it consists of both movements and rotations. Note also that the current system has problems for multiplayer mode. For example, if the turbulence were set to .5 (which should be pretty bad), a J3-cub and a Boeing 747 flying into the same airport will experience the same turbulence, while in reality turbulence that would tear a wing off a J3 cub might not do much more than jiggle the drinks in the 747. As soon as you consider a world with more than one plane flying at once, we have to think about modelling the turbulence not by its effects on the plane, but by its source air motion. All the best, David - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] Flight Gear runtime failure
Csaba, Indeed. I have a Radeon X1950 pro. Am I out of luck? Thanks again, Jim Reinsberg Csaba Halász [EMAIL PROTECTED] wrote: On 10/8/07, James Reinsberg wrote: [EMAIL PROTECTED]:~/applications/FlightGear/source$ fgfs *** glibc detected *** fgfs: free(): invalid pointer: 0x08746e10 *** === Backtrace: = /lib/tls/i686/cmov/libc.so.6[0xb74037cd] /lib/tls/i686/cmov/libc.so.6(cfree+0x90)[0xb7406e30] /usr/lib/libstdc++.so.6(_ZdlPv+0x21)[0xb759ed11] /usr/local/lib/libosg.so.25(_ZN3osg16DrawArrayLengthsD0Ev+0x37)[0xb7aae767] Let me guess: ati driver? -- Csaba - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel - Moody friends. Drama queens. Your life? Nope! - their life, your story. Play Sims Stories at Yahoo! Games. - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] autopilots, adverse aileron yaw and jsbsim questions
I helped implement this with Tony a few years ago. As I recall, the value was from 0 to 1, where 0 represents no turbulence, and 1 represents the most severe turbulence that we model. You couldn't represent turbulence simply in feet/second, because it consists of both movements and rotations. Note also that the current system has problems for multiplayer mode. For example, if the turbulence were set to .5 (which should be pretty bad), a J3-cub and a Boeing 747 flying into the same airport will experience the same turbulence, while in reality turbulence that would tear a wing off a J3 cub might not do much more than jiggle the drinks in the 747. As soon as you consider a world with more than one plane flying at once, we have to think about modelling the turbulence not by its effects on the plane, but by its source air motion. Dave Yes, the rotational aspects of turbulence will be dependent on the specific aircraft characteristic length in the relevant axis - we've got that covered, so different sized aircraft will see rotational effects of turbulence correctly (theoretically ;-). And we have a direction unit vector and a magnitude vector, which should take care of it all. What I haven't seen yet is how the magnitude of the turbulence is controlled in JSBSim from a setting that is passed through in JSBSim.cxx (the interface). I'd expect to see a maximum value of some kind, because a normalized gain doesn't tell me anything. A value from 0 to 1 is fine, if a total expected turbulence magnitude is passed in, because I want to convert it to a wind velocity. A total range of from 0.0 to 1.0 ft/sec isn't representative - and I'm sure that's not what is intended - but that seems to be what is happening with turbulence. Jon - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] autopilots, adverse aileron yaw and jsbsim questions
I don't think that's the primary issue ... although there might be a /secondary/ issue with the kap140 being more vulnerable to bad handling characteristics than some other autopilots are; I don't know. I recommend fixing the flight dynamics first, and only then looking to see what secondary issues might exist. Other oddity in the flight dynamics is: much too much rolling moment due to changes in engine power setting. I would have tried to fix this, but I didn't see any parameter to control this in the configuration file. I know there is some irreducible rotational drag from the propeller, and this rightly belongs in the engine/prop configuration ... but there are other things such as asymmetric wing-root incidence that are used to counteract it ... I didn't do an exhaustive search, but I didn't see that anywhere. There are many other oddities, such as fuel never being consumed from fuel tanks, effective mixture not being sensitive to altitude, EGT reading high and insensitive to mixture, etc. etc. This would be interesting - I've not yet seen fuel not being consumed. Which aircraft? I wonder which version of JSBSim you are using in FlightGear? As for engine characteristics being off, unfortunately our piston model author has been very busy (even unresponsive). If I have to fix that, it's going to take some extra time, which I have very little of. If someone else wants to take a look at that, it would be really great. I'd help out as much as I could. I've been wondering if it would be a good idea to turn off some of the dynamic aero derivatives and see what happens to the performance and handling. It could also be that the DATCOM file used to create the Seneca II derivatives needs to be tweaked a little bit. If we can determine some real values for some of the derivatives, the DATCOM file can be seeded with those to help produce better results. Jon - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
Re: [Flightgear-devel] autopilots, adverse aileron yaw and jsbsim questions
More on turbulence. At least in the copy of JSBSim.cxx that I have there is this code in Copy_to_JSBSim: tmp = turbulence_gain-getDoubleValue(); Atmosphere-SetTurbGain(tmp * tmp * 100.0); tmp = turbulence_rate-getDoubleValue(); Atmosphere-SetTurbRate(tmp); There are two gains that come into play. One is from FlightGear (0.0 to 1.0, as Dave M. pointed out), and the one eventually sent to JSBSim, which is in ft/sec. It looks like the one set in JSBSim can vary from 0.0 to 100.0 ft/sec. That is the maximum value expected. That seems high to me. Today I plotted out some turbulence values in a scripted run using the C172. That was instructive, and I am making some adjustments. Jon - This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now http://get.splunk.com/ ___ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel