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Simple PID AutoThrottle Scripts


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AutoThrottle_TJ.lua,  AutoThrottle_TP.lua  and AutoThrottle_CRJ.lua are simple PID (Proportional, Integral, Derivative) implementations of an Autothrottle for TurboJet, TurboProp, and the AeroSoft CRJ aircraft, respectively (the Aerosoft CRJ is somewhat of a special case because of unique throttle coding). These scripts work reasonably well on the Flysimware Learjet35A, Falcon50, MU-2, and on the Aerosoft CRJ aircraft.  I have been told the Autothrottle.TJ script works with the Aerosoft DC-8. I'd be interested in hearing how these scripts work on other aircraft. There are parameters at the top of the scripts that you can experiment with if necessary for a particular aircraft. The TurboJet and TurboProp scripts assume standard FSX or P3D throttle coding and should work for aircraft with up to four engines.

To try out an autothrottle put the script in your modules folder and use FSUIPC in the usual way to assign a key or button to the appropriate script to activate it. When activated a window will open asking for a target IAS between 50 and 500 Kts. Of course you need to use a target IAS that is reasonable for the a/c. If the A/T is running you will need to call the script again to change the target IAS, or to turn the A/T off by entering a * instead of an airspeed value. You could also use the FSUIPC LuaKill option to quickly exit a script. It is best that the AP is on and the a/c is stable and reasonably close to your target IAS when the A/T is activated. If you ask for large IAS changes it can take a while for the IAS to finally settle down.

When the A/T is running you will see a green bar across the top of your screen with the target A/T IAS.  Note that you can grab the right side of the green bar with your mouse and resize the bar down to a small display. You can also drag and reposition the green bar to where you want it.





AutoThrottle_CRJ.lua AutoThrottle_TJ.lua AutoThrottle_TP.lua

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  • 5 weeks later...

I have updated the autothrottle lua scripts to work with Mach# as well as IAS in knots.

Each autothrottle script defaults to airspeed values in Knots below its crossover altitude, and in Mach# above its crossover altitude. The crossover altitude for the TurboJet and CRJ scripts is currently set at about 29000ft. For the TurboProp and C441 scripts it is set at about 24000, and at about 22000 for the MU2 script (crossover altitudes can be changed with a text editor). When a script is activated you will see


When climbing or descending through the crossover altitude the autothrottle automatically switches to Mach# or Knots, respectively. In addition, a key or button can be setup through FSUIPC to manually switch the autothrottle back and forth between knots and Mach# at any time.The corresponding A/T target speed displays when the script is running looks like this


AutoThrot3C441.lua AutoThrot3CRJ.lua AutoThrot3MU2.lua AutoThrot3TrbJet.lua AutoThrot3TrbPrp.lua

SetUp Autothrottle Lua Scripts.docx

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