I found this video and per the video and with some read up, I did tune my F450 Quad (with stock DJI motors, ESCs and props) Quad set in (X) configuration. APM 2.5 on board. I focused on 4 basic parameters initially. I used the channel 6 option to tune the values during flight. Would you please read below and make comment/answer my questions as applicable?
1.Rate_Control_P: I started with this one. I read that this is the single most important parameter. I flew in Acro mode and change this parameter while flying. I found a sweetspot; landed and permanently wrote it. It came to be 0.1420 for my taste.
This paremeter (Kp) acted just like I am adding a negative expo (positive for JR) or reducing stick travel rate. So I am pretty sure I could have gotten the same thing by just playing the Tx menus instead of this Kp value. I am not sure what the real difference is. And I am not sure if one should adjust the Tx parameters before messing with this Kp value. Any comment appreciated:)
2.Rate_Control_I: Flew in Acro mode again. I tried to use the same approach for this one too but I wasn't able to get much. No matter what I did, my quad wasn't holding the angle. I think I was changing the I value between 0.100 and 0.200 and I almost saw no change between the min. and max. values so I left it at 0.15.
I am not saying my quad was self leveling like in the Stabilize mode but it wasn't holding the angle as soon as I let go off the sticks. What should I do here?
3.Stabilize_Control_P: This time I flew in stabilize mode. My starting value was 4.5. I was thinking I would see some oscillation. I didn't. But it was twitchy to my taste. I like smooth flying machines. I reduced it down to 2.5 level and it flew okay but then I didn't want it to be unstable in gusty winds so I brought it back up to 3.3 and left it there.
4.Stabilize_Control_I: I ran out of battery by the time I get to this. I checked and my Quad was coming down okay. Not super stable but it wasn't so wobbly. The default value is 0.00 for this one. I think I will try 0.02 when I get a chance to see if it will work better.