Calling all Custom Multi-Copter Pilots!

I'm going to do what is called a "pull" to made changes to the custom code regarding custom shaped copters.  

This change in code would only impacts irregular shaped quads, hexas, and octas when the pilot specifically opts to go custom versus the default (the standard X or +).  You have a custom quad if the:

o aspect ratio <> 1 (length is different than width).

o rotors are non symmetric around the

   - forward axis (y) going through the center of gravity (CG)

   - sideways axis (x) going through the CG

   - vertical axis (z) going through the CG

o has a front that is more open for a camera

o deviates from the pictures of a a + or X for the quad, hexa, or octa

o this includes ships described as spider, V, H, U, 88--88, C, etc.

o motor spin direction(s) are different than the pictures

o your CG is pushed somewhere else besides the centroid of the motors.

The advantages of going custom is that the motor factors will be tuned to the coordinate/spin system of your copter versus the coordinate/spin system of the regular copter.  They will fly better.  Pilots will probably not notice small deviations nor would they see significantly improved flight times.  Large deviations might be noticed and provide noticeable changes in flight duration.

Please reply with the coordinates and rotation direction of each rotor.  For example,


the owner of this copter would reply (motor number, x, y, CCW/CW):

o 3, -300, 200 CW

o 1, 300, 200 CCW

o 2, -300, -200, CCW

o 4, -300, 200 CW

Please note:

o The center of gravity of any quad spider or V is not where the bars cross.  The bars always cross behind the CG.  .

o The CG is the center of the coordinates or (0,0) where x=0 and y=0

If you decide to participate by replying, the idea is that will be able to access your custom motor factors without having to compile firmware.  No promises at this point.  First we see what's out there.  

If you have any questions or difficulties in doing this, let me know so I can help.

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  • Thanks for the reply, we are working some long days right now. As soon as I can i will get some info together and email it to you. We are trying to keep it private right now. I will be in contact soon.

                 Thanks again,

                         Jon Turner

  • MR60

    Feel free to contact me directly at and provide more detail about the X8 (or if you don't mind being public then we can use the forum). If needed, I'll model the X8 config worksheet and send you a copy and send you a copy of the draft software mod user manual.

    - just need the size-layout of each motor axle from the top view.

    - a photo would also help but not absolutely needed.

    - certain offsets in z (as long as the props spin parallel to each other) don't matter from a motor factor config point of view (it does change the CG of z).

  • Hi Forrest,
    is this something you are still working on. I am involved in a large x8 with staggered front to rear rotor height, and am interested in working with someone to help configure this to fly with ph2.1. We are ready to fly now, but may need some help with config/tuning. You interested?

  • T3
    Forrest you aways does great work. Nicely done.
  • MR60

    Attached is a worksheet for custom quads.  It looks like:


    I have another for custom octas and another for custom hexas if you need one.  You can enter the quad's front width, rear width, and length (easier measurements than the coordinates).  You can also enter prop direction (1 for standard and -1 for reverse).  The coordinates are then calculated.

    Let me know if you have any questions or would like improvements to the worksheet.  See attached.

    Custom Quad CAD.xlsx
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