D800 X8 with QGC and Pixhawk 2.1

[gjk]

Dear All,

I am trying to set up a D800 X8 with Pixhawk 2.1,as described in
http://www.dys.hk/Download/Multicopter/EN%20D800-X8%20manual.pdf
all four top rotors are CCW and all the bottom ones are CW. I see that
@LorenzMeier owns octo coaxial wide, what would be needed to set up
the D800 X8 ? I am not sure we have the experience to do so.

Respectfully G

[gjk]

Reading more about the top being CCW and the bottom CW
I wonder whether that is a stable flight configuration ? Need
help configuring.

[lamping.ap]

X8 frame config on PX4

Bart, Sry but I don’t get you. In multi_tables.py, X8 octa_cox = [ [ 45, CCW], [ -45, CW], [-135, CCW], [ 135, CW], [ -45, CCW], [ 45, CW], [ 135, CCW], [-135, CW], ] So according to this the picture i made should be correct? Below is the same pic as above, just slight adjust on style. [image] The X8 frame now looks like this. It is a 350mm frame, pretty small. [image] I did not fly it yet, just tested by holding it with my hands. The pitch/yaw/roll feels OK. Will do more t…

[rolandash]

You can refer to this manual (on page 6) for coaxial X8 motor map.
Though the diagram in manual is for MindPX, it should apply to all PX4 compatible flight controller.

[gjk]

Thank you @lamping.ap and @rolandash. Maybe I was too short in my
question, the D800X8 has rotors 1 2 3 4 (all the ones on the top) in CCW
and 5 6 7 8 (all the ones on the bottom) in CW. From both your posts I
read that 1 2 3 4 alternate between ccw and cw and 5 6 7 8 alternate
between ccw and cw again. Completely different setup ? Do I misunderstand ?

[rolandash]

@gjk

A popular mis-understanding about rotor is, CW/CCW does not mean the direction of motor rotation, as motor can rotate either clockwise or counter-clockwise, by just changing the order of input cables. So it makes no sense to identify a motor type by their spinning direction.
Instead, CW or CCW motor refers to the thread direction on motor shaft, rather than the direction of rotation, in terms of motor types. That is how you specify motor type when you order from motor vendors.
Why CW/CCW motor matters as it needs to be matched with right propeller type, i.e., push propeller and pull propeller, to generate self-locking effect.
The output thrust vector of a motor setup can be regarded as a function of motor type(CW/CCW), propeller type (push/pull) and input cable order. It is possible to have same output with different combination of inputs.

So it is very ambiguity in D800’s manual that what its marked ‘CW/CCW’ really means. A good guess is since it looks like DJI style of motor layout, so probably the frame is specially designed for DJI flight controller, that all top four spinning ccw and cw in bottom.

PX4 uses a different motor mapping layout, and it is defined in PX4 code. So better to follow PX4 style if use PX4 compatible flight controller otherwise very confusing.