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Aircraft weight affects AI behaviour

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If your AI aircraft won't take off: check your weight! Changes to default B737 aircraft.cfg://empty_weight=100792 // (pounds)empty_weight=300792 // AI test 1-> aircraft accelerates very slowly, is unable to take off within runway length, later crashes//empty_weight=100792 // (pounds)empty_weight=1007920 // AI test 2-> aircraft gets stuck on the runway, unable to moveHave fun! :)ckfly

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Another indication that the flight dynamics of the plane are important to AI flight - thanks!-- Tom GibsonCalifornia Classic Propliners: http://members.aol.com/tgfltsim/index.htmlAlcoHauler Locomotive Page: http://members.aol.com/alcohauler/home/alcohaul.htmlFreeflight Design Shop: http://www.freeflightdesign.com/ San Diego Model RR Museum: http://www.sdmodelrailroadm.com/Drop by! ___x_x_(")_x_x___

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I didn't get a chance to read the AI forum but the 767-200's I downloaded for Delta and United taxi and accelerate, but do not take off. I tryed using a different .air file but no luck. Maybe in the model itself?probably not related to this but I'll check anyway.Thanks for the info

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It's definitely related. Replace the AIR file with a default one like the 737 or 777. I also replace the aircraft.cfg file with the one corresponding to the AIR file, using the fltsim, general, contact points, lights, and cruise speed sections from the original aircraft.cfg file.As it turns out, I'm replacing all of my AI aircraft FDE's with the King Air ones, since it's one of the few planes capable of propliner speeds (i.e. around 240 kt cruise speed) which lands without "ballooning" on flare. I reduce the Braking Factor in the AIR file to lengthen it's landing run and reduce the Maximum_torque and Elevator_effectiveness values in the aircraft.cfg file to lengthen the takeoff run and avoid jackrabbit takeoffs. Works pretty well, but is still a compromise...Hope this helps,-- Tom GibsonCalifornia Classic Propliners: http://members.aol.com/tgfltsim/index.htmlAlcoHauler Locomotive Page: http://members.aol.com/alcohauler/home/alcohaul.htmlFreeflight Design Shop: http://www.freeflightdesign.com/ San Diego Model RR Museum: http://www.sdmodelrailroadm.com/Drop by! ___x_x_(")_x_x___

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I've found a way to get the airplanes to stop ballooning, at least works for me so far. Using the default 737-400 airfile, I used aired to edit the flaps lift section. The default on my system was 1.5, I changed it to 0.5. My AI aircraft were approaching at a unrealistic negative attitude causing them to over compensate during flare. It's all due to the aircraft having too much lift when the flaps are lowered. Also I changed the oswald efficiency factor in the CFG file to reduce the extreme climb rate of the AI Traffic aircraft. The default was somthing like 0.85, I changed it to 0.35. Now instead of AI climbing out at 8000ft per minute they climb at about 4000ft per minute.Hope this works for you too.

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Tom,"I reduce the Braking Factor in the AIR file to lengthen it's landing run"Does this work for AI? I wonder, because a while ago someone said it would make no difference.BTW, adding to my 1st message: - "station_load" shows the same effect as "empty_weight". Put in some passengers... :)ckfly

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>least works for me so far. Using the default 737-400 >airfile, I used aired to edit the flaps lift section. The That's good news, flaps lift is working, too!>Now instead of AI climbing out at 8000ft per minute they >climb at about 4000ft per minute. Try reducing static_thrust by about 10% and add a little passenger load. The 737 is overpowered anyway.ckfly

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Yes, it does work. However, you have to reduce it by a *lot*. I currently have my aircraft braking set between 1767 and 6767, depending on aircraft (max is 32767).Hope this helps,-- Tom GibsonCalifornia Classic Propliners: http://members.aol.com/tgfltsim/index.htmlAlcoHauler Locomotive Page: http://members.aol.com/alcohauler/home/alcohaul.htmlFreeflight Design Shop: http://www.freeflightdesign.com/ San Diego Model RR Museum: http://www.sdmodelrailroadm.com/Drop by! ___x_x_(")_x_x___

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Thanks!I think we gonna see more realistic flying AI soon!(I'm digging into the landing sequence now. There's a distinct approach profile showing in the AI Tactical Display.)ckfly

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An additional factor you may want to use is the elevator range setting in the cfg file. Reduce the up - down ranges if you are having a "ballooning" problem on level flight. You can also increase the MOI to slow the frequency of the ballooning. Works like the physics in the real world. More MOI (moment of interia), slower system response.Neat part of it is, you can adjust the MOI and not impact the mass. Wish I could have done that in the real world.The people who have built these simulation systems are far smarter then many have given them credit for. This simulation digital model does react to the laws of physics if you look and observe closely. Review your physics and you can make the aircraft do just about anything you want. If your not sure about your physics, then learn the "Design of Experiments" to reduce your test/iteration time.The point is, fix things if you don't like the way the aircraft is modeled. You can do it, it is science, but not rocket science. Keep in mind, you solve a diffential equation at every stop sign when you are driving and going to merge with traffic.Regards,Bob

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Thanks Bob,>The people who have built these simulation systems are far >smarter then many have given them credit for. This >simulation digital model does react to the laws of physics >if you look and observe closely. Review your physics and >you can make the aircraft do just about anything you want. The problem is (was) until a few days ago I had the strong impression the AI would not use the regular FS2002 flight dynamics system - but some kind of simplified AI algorithm instead. This was due to the mass of people dropping default B737 airfiles in every aircraft to be used as AI traffic. But now we should know better.>If your not sure about your physics, then learn the "Design >of Experiments" to reduce your test/iteration time. No problem with physics, but this is just for fun! :)ckfly

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Could or would some kind soul explain how all this is done?I've reached a plateau in my learning curve. FS2K2 is my first time with this series, and while I'm not a dummy ( I've used TTools and am capable of adding textures) I'm at my wits end trying to keep up with you experts on file tweaks and massages and swap-outs. Every time I think I've got it right............I don't.I'm stuck! I hope I'm not asking too much, but I really want to learn more of how this is done. Any tips?ThanksRick

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I suggest reading "Flight Dynamics" by Tom Goodrick. There are some more documents by other designers, too. Just search the internet.You will need "AirEd" by William M. Roth, it's a *real* airfile editor.There is some interesting activity by a group (www.avhistory.org) working on so called "1% airfiles" for CFS/CFS2. ckfly

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Thanks to the flaps lift tip, I have changed over all my large propliners back to the 737 FDE. I set the flaps lift (in the air file) to 0.9, the elevator_effectiveness to 0.8 and the engine power to 13000 (both in the aircraft.cfg file), and this gives a pretty good simulation during takeoff and landing. Thanks again!-- Tom GibsonCalifornia Classic Propliners: http://members.aol.com/tgfltsim/index.htmlAlcoHauler Locomotive Page: http://members.aol.com/alcohauler/home/alcohaul.htmlFreeflight Design Shop: http://www.freeflightdesign.com/ San Diego Model RR Museum: http://www.sdmodelrailroadm.com/Drop by! ___x_x_(")_x_x___

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