Autopilot Feedback Control Facility

[dfournie]

Has anyone had any luck using this feature? I've been experimenting with it by sending the correct strings of data to the pitch and roll (0700 - 0717, and 0718 - 072F) offsets and it doesn't appear that FS is reacting to the external control inputs at all.

[Pete Dowson]

Has anyone had any luck using this feature? I've been experimenting with it by sending the correct strings of data to the pitch and roll (0700 - 0717, and 0718 - 072F) offsets and it doesn't appear that FS is reacting to the external control inputs at all.

It's being used okay. Even the speed control (which isn't so well behaved) is now being used successfully for taxiing.

Let me know what you are doing and I'll try to spot where you are going wrong.

Regards,

Pete

[dfournie]

Welcome back Pete. I've since successfully got it to work. There seemed to be a sign problem (+/-) - I think I had them reversed. The only things I'm having trouble with now are the fine tuning of the roll and pitch when the target value has been reached - while the autopilot is attempting to maintain a straight and level state, and trying to get FS2004 to match my external flight director for commanding it's roll/pitch. Even with higher numbers plugged in for max rate of degree change and maximum total degree pitch/roll, I sometimes have a slight delay in FS2004 in trying to keep up with the roll and pitch commands it is getting. I know there is some limit with the roll/pitch authority provided by the King Air flight model I'm using. There is a considerable amount of wing rock and in certain situations some dutch rolling tendencies. Can you shed some light on the "fiddle factor' values? Are these just for ultra-fine tuning for the autopilot "gains" I'm using to preciesly control the FS2004 flight model? I'm fairly sure I've got the macro and micro values for pitch/roll control pretty much dead on.

[Pete Dowson]

I know there is some limit with the roll/pitch authority provided by the King Air flight model I'm using. There is a considerable amount of wing rock and in certain situations some dutch rolling tendencies. Can you shed some light on the "fiddle factor' values? Are these just for ultra-fine tuning for the autopilot "gains" I'm using to preciesly control the FS2004 flight model? I'm fairly sure I've got the macro and micro values for pitch/roll control pretty much dead on.

The fiddle factors are just that -- non-dimensioned multipliers adjusted interactively by me to get the best results. I tried them with most, but not all, of the default FS aircraft, and got good results except for speed control where the oscillations were still present when I released it.

I'm sorry, but optimising is really a trial-and-error process. If you do find better values please let me know, but the current ones are certainly good with both the Cessnas and Boeings. I could imagine there'd be problems with aerobatic aircraft with fast roll rates, but it surprises me that a King Air doesn't stabilise quickly.

Regards,

Pete