Question About Modifying AI Taxiing Turn Radius

[Guest]

Does anyone know which value is modified in an AI aircraft's .air file to change the taxiing turn radius? I have a problem with all PAI and UT B767s turning much too wide while taxiing and overshooting the turns. Taxi speeds are 23 straight line and 4 for both tight and wide turns, so speed is not a factor here. The B777s and other large aircraft all "turn on a dime", but the 767s turn much wider. I have used both the UT .air files and the PAI .air files and both result in the same wide turn radii.TIA for any suggestions or assistance!Doug3.06Ghz P4 533FSB512 MB RAMBUS RAMSony CPD-G410R 19" CRTRadeon 9700 Pro (Not O/C)SB Audigy 2120 GB ATA Ultra DriveMS Sidewinder Force FB ProWinXP Pro SP1DX 9.0a

[Guest Milton]

Not sure if AI is different but two methods to try :In the aircraft,cfg:1. Adjust the 8th parameter in the contact point.0 for nose wheel degrees of deflection to 45-60, or2. In the Airplane_Geometry Scetion, adjust the rudder deflection value to more at 45-60 degreesHope this helpsMilton

[Guest]

Milton,Thanks for the suggestions.Regarding your first suggested item, I checked the aircraft.cfg file for both the UT B762 and B772 and the contact_point.0 parameters (8th position) were identical (both 55.920). However, the B762 turns wide and the B772 turns on a dime. Not sure what that value really does in this case. :-hmmmI checked the {airplane_geometry} section for each but could not find an entry for rudder_deflection. I then checked the aircraft.cfgs for several other aircraft in my stable (AI and non-AI) and likewise couldn't find a rudder_deflection value. If I add the value to the {airplane_geometry} section, is this the suggested format:{airplane_geometry}rudder_deflection=60.00Thanks for helping with this! :-zhelpDoug3.06Ghz P4 533FSB512 MB RAMBUS RAMSony CPD-G410R 19" CRTRadeon 9700 Pro (Not O/C)SB Audigy 2120 GB ATA Ultra DriveMS Sidewinder Force FB ProWinXP Pro SP1DX 9.0a

[Guest]

After much trial and error testing with editing aircraft.cfg files, .mdl files, and .air files I did not discover any settings that changed the B767s ability to turn more quickly and with more authority. I finally decided to set the tight turn 1 & 2 settings (with AI Traffic Speed tool) down from 4 to 2 knots and voila! the problem appears solved. This however, is a problem because taxi speeds in corners are now very, very slow. All in all, until some better solution appears, this will have to do.Thanks again to all who assisted with suggestions.Doug3.06Ghz P4 533FSB512 MB RAMBUS RAMSony CPD-G410R 19" CRTRadeon 9700 Pro (Not O/C)SB Audigy 2120 GB ATA Ultra DriveMS Sidewinder Force FB ProWinXP Pro SP1DX 9.0a

[Guest Douglas K]

The rudder deflection value in the Airplane_Geometry Section that Milton referred to is entered as - rudder_limit - see below:elevator_up_limit=22.5 //Degreeselevator_down_limit=19.5 //Degreesaileron_up_limit=20.0 //Degreesaileron_down_limit=20.0 //Degreesrudder_limit=26.0 //Degrees <-------- HEREelevator_trim_limit=20.0 //Degreesyou may also want to try moving the nosegear longitudinal position aft (in the contact_points section, position.0 entry #1) by several feet or more to place more weight on it, this usually results in a smaller turning radius.point.0=1,---->30.00,<---- 0.00, -8.10, 1181.1, 0, 1.442, 55.92, 0.8, 2.5,And you should try changing the airfile entry Cn_dt-Yaw Moment-Thrust found in Rec 1101 to the highest value possible (enter all 9's for the heavy A/C), this works on the prop A/C, and it seemed to work on the default 737 as well. How it will behave with AI I cannot say.

[Guest]

DouglasYou said:>you may also want to try moving the nosegear longitudinal>position aft (in the contact_points section, position.0 entry>#1) by several feet or more to place more weight on it, this>usually results in a smaller turning radius.>>point.0=1,---->30.00,<---- 0.00, -8.10, 1181.1, 0, 1.442,>55.92, 0.8, 2.5,I tried your suggestion and had to move the values way back (from 60 to 20 to get the proper response. It worked and the turns are satisfactory now! :) Thanks a million for the suggestion!Doug3.06Ghz P4 533FSB512 MB RAMBUS RAMSony CPD-G410R 19" CRTRadeon 9700 Pro (Not O/C)SB Audigy 2120 GB ATA Ultra DriveMS Sidewinder Force FB ProWinXP Pro SP1DX 9.0a

[Guest Douglas K]

Great!I like happy endings!!

[Guest]

Douglas,You said:>And you should try changing the airfile entry Cn_dt-Yaw>Moment-Thrust found in Rec 1101 to the highest value possible> (enter all 9's for the heavy A/C), this works on the prop A/C,>and it seemed to work on the default 737 as well. How it will>behave with AI I cannot say.Although I am happy now with the way the B767s taxi, I was curious about your last tip in your original response to me. You refer to a line "Cn_dt-Yaw >Moment-Thrust" found in the default 737 .air file, but a diligent search of all my .air files fails to turn up an entry matching yours in Record 1101. Could you please enlighten me as to exactly which Record 1101 entry you were refering to?Thanks again! :)Doug3.06Ghz P4 533FSB512 MB RAMBUS RAMSony CPD-G410R 19" CRTRadeon 9700 Pro (Not O/C)SB Audigy 2120 GB ATA Ultra DriveMS Sidewinder Force FB ProWinXP Pro SP1DX 9.0a

[Guest Douglas K]

You didn't mention what airfile editor you are using, I'm using AirEd and I have Ron Freimuth's ini file dated 4/11/03 installed. The original ini file for AirEd called this entry found under Rec 1101:*Yaw Moment-Prop Effect On Rudder=0.000000it was set to zero in the default 737 airfile, I changed it to this:*Yaw Moment-Prop Effect On Rudder=9999999999999998.000000This works great on the propellor A/C, (although for the smaller and lighter types a value of 0.005 0r 0.006 is a better idea unless you want an A/C that will spin like a top when you try to turn! I haven't noticed any effect on the flight dynamics when making this change, only to the ground handling) but looking into it a little further just now with the Microsoft 737, I see that it doesn't make any difference, both the default and modified airfiles turn the A/C in about the same radius, on my computer anyway. It looks as if the original ini file designation of PROP Effect On Rudder was correct, and jet thrust has little or no effect. I see that Aircraft Airfile Manager calls this entry Cn_dp Yaw Moment-Prop Effect as well, so perhaps jet thrust is not going to work!Of course you would have to test this hypothesis on several different jet airfiles before coming to a definite conclusion about it, something that I don't have time for, and am not interested in as I don't use the jet airliners at all. You may want to experiment with it, but at this point, as far as the MS 737 is concerned, it doesn't look too promising.

[Guest]

Thanks, Douglas... I appreciate the time you've taken to help me with this issue. I'll post back here in a day or so after I've had some time to test the .air file settings. BTW, I'm using AirEd as well, but version 1.52 dated 9-12-2000! Guess I better update :)Doug3.06Ghz P4 533FSB512 MB RAMBUS RAMSony CPD-G410R 19" CRTRadeon 9700 Pro (Not O/C)SB Audigy 2120 GB ATA Ultra DriveMS Sidewinder Force FB ProWinXP Pro SP1DX 9.0a