[Jsbsim-devel] F-16 Stability problems

[Bruce <bcl...@gm...>]

I am working with the F-16 model that is in the current version of JSBsim.  I seem to be having some stability issues that I can not account for.   The model will occasionally start oscillating in pitch.  Sometimes I can get it to stop with a hard pitch maneuver other times it seems to settle out on its own.

 

The second problem I am having may be related.  The model does not stay straight and level with zero stick input.  It will gradually roll over or pitch up.

 

I tried to set the autopilot based on examples I found in the mailing list.  I added 

 

      <property> ap/heading_setpoint <property>
      <property> ap/heading_hold <property>
      <property> ap/altitude_setpoint <property>
      <property> ap/altitude_hold <property>

 

to the output section of the f16.xml file and added heading set point value of 270.0, heading hold cmd value of 1.0, altitude setpoint value of 10000 and altitude hold value of 1.0 to the output data stream with the other cmd parameters.  I don't get any errors but I also don't see any change in the models flight.  I would really like to get a basic attitude hold so I can programmatically hold straight and level or go in to a standard rate turn based on pilot input.

 

Any suggestions would be greatly appreciated.

 

Bruce