Aerodynamic Forces Pink/Green?

[myrky]

Blue - Lift from wings

Cyan = Lift from Air intake/engine?

Red - Drag

Yellow - Thrust/Control surface lift. 0 underwater  

Pink - ?? outside the part, Tracks Yellow 

Green - ?? Inside the part. One for each propeller, increases with motor speed. 0 RPM dances around randomly. Flips direction with "Rotation Direction" or "Invert Direction", (Those two things appear to do the same thing, are they different?) right hand rule? Angular Velocity? 

 

Other askers, that didn't get definitive answers:
https://steamcommunity.com/app/220200/discussions/0/3140616601468124007/
https://www.reddit.com/r/KerbalSpaceProgram/comments/fusq3o/can_anyone_on_this_earth_please_explain_the/

[AHHans]

Let's see:

Blue = Lift from wings
Well, you got that. With "direction of lift" == perpendicular to the plane of the lifting part.

Red = Drag
That's also an easy one. Here is "direction of drag" == in the direction of the apparent wind.

Yellow = Lift from control surfaces
Like blue, but can change direction when the control surface moves

Cyan = Body lift from non-wing parts
If you move a non-wing part at an angle through the air then it will generate not only drag but also some lift. Think e.g. about a structural panel that's angled like a wing. (But I'm not 100% sure about that, so feel free to correct me.)

Green = Indication of rotation direction and  angular speed
See KSP 1.9.0 / BG 1.4.0 changelog: "* Blade rotation axis shown as green arrow in aero debug display. Length is logarithmically proportional to rotation velocity (vessel relative)."

Pink = "Cheated extra thrust/lift of propeller and helicopter fan blades"
The game engine can only handle a rather small rotational velocity (it is approximating the rotational motions with linear motions), that would result in rather small lift from any kind of realistically sized propeller or helicopter blades. (Real propellers rotate much faster.) So SQUAD "cheated" some extra lift onto the propeller and helicopter blade parts to give the propellers/rotors some reasonable thrust.