More info please on quadcopter frame types: V vs H vs X

There’s very little info to be found in the documentation (as of writing) about the listed frame types: … electframe

Also I can’t find the latest source code (3.0.1) to read what’s in libraries/AP_Motors/AP_MotorsQuad.cpp

Specifically, I’d like to know:

  1. What the chosen angles for the V frame are. In 2.9.1 the angles are the same as for an X frame, and float values instead of int constants are used for the direction.
  2. Are the motors of an H quad supposed to rotate in opposite directions to an X quad? If so, why?


from my point of vue, the frame type is meaningless. what’s important is the relative position of the propeller. for au quad, xHV shapes are quite the same and for the APM it is the same control.

the difference is only cosmetic

wrong. i just tried out x vs h on a quad ‘h’ frame. it oscillates in yaw if the config is x, because h frames flex so much more. perfectly stable with h config. makes a huge difference.