I'm interested in getting a more rigorous understanding of what each flight mode means, and how the autopilot behaves in each mode. I think it would be very helpful to have fully detailed explanations of each flight mode and what it does and does not do. For instance, I have several questions to begin with that I would really like to know the anwer to:
1. In manual mode, the autopilot has no effect on the control surfaces of the airplane. But in stabilize mode, the autopilot tries to keep the attitude of the airplane set to wherever you have your control inputs set to (or so I've read in the manual). Does stabilize mode also try and keep the altitude constant? I tend to think not as when I put my plane in stabilize, it slowly lose altitude over time. Are they're any other control loops running other that pitch and roll?
2. How is fly by wire different from stabilize mode?
3. I know that there are many different control loops running on the ardupilot. It would be great to know which ones are active in which modes. For instance, in auto mode, the nav roll control loop is clearly running, whereas in stabilize mode, it obviously isn't. This is an easy case, but there are more nuanced cases. I would appreciate any info people may have on all the different control loops and when they are active.