Quad X motor rotation opposite of ArduPilot diagram

ArduCopter
1

Hello,

I am building my first quadcopter using ArduPilot (Copter 4.6) on a Pixhawk 6C.

Frame type is Quad X. Motor numbering and output order are correct and verified in Mission Planner using the motor test.

However I noticed that my motor rotation pattern is the mirror image of the standard ArduPilot diagram.

My setup is:

Front right: CW motor
Rear right: CCW motor
Rear left: CW motor
Front left: CCW motor

So effectively:

Front left: CCW
Front right: CW
Rear left: CW
Rear right: CCW

This is the exact opposite rotation direction of the standard Quad X layout, but the motors are still arranged diagonally (2 CW and 2 CCW).

Important details:

  • Motors: BR2212 980KV with self-tightening CW/CCW threaded shafts

  • Props therefore cannot easily be swapped

  • Motor order is correct (A,B,C,D)

  • Props produce thrust downward

  • The drone actually flew stable during a short hover test, only a small drift in stabilize mode.

My question:

Is there any downside in ArduPilot to running the mirror motor rotation pattern, or is it perfectly acceptable as long as torque balance is maintained?

I am mainly wondering if this could affect:

  • yaw control

  • autotune

  • PID behaviour

Or if ArduPilot handles both patterns equally well.

2

Just choose the QUAD H frame type. Despite being labeled as an H frame, the only difference under the hood is motor rotation.

You will run into significant issues with yaw direction otherwise.

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3

FWIW, when I had motors spinning in the opposite direction in ArduPilot, I temporarily connected the ESCs to a BetaFlight flight controller and reversed the motors from within BetaFlight.

I personally prefer the BetaFightXReversed frame type.

FRAME_TYPE = 18. I find the reversed props can handle small twigs and grass much better than the normal rotation direction.

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4

Yep, that’s the exact same motor scheme as QUAD H with slightly different output numbering to hopefully make it easier to route wires to 4in1 ESCs. The net result is identical.

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