Thrust vectoring coaxial Drone Update


 Just a quick update for the thrust vectoring coaxial drone project,


Maxxprod Himax contra-rotating brushless motor CR2805,

7x5 props replaced by T-Motor carbon fiber 9x3 resulting in more efficiency.

Flight time is about 15 minutes with Fatshark HD pilot and 12 minutes with a Gopro 3. Could be even better with a more adapted motor. The advantage of this system is to allow large props with little frame (the 3D printed frame of this coax weights less than 30 grams) resulting in a very good efficiency.

Flight controller is a CC3D revolution with a standard coaxial vehicle config.

The system seems to not accept too much the integral (often resulting in a counter pendulum effect during fast pitch forward translation but maybe it can be a variable overshoot??) but no pendulum effect with a simple P (no I nor D) for the inner loop (acro) and a simple P (no I) for the outer loop (attitude). With this config, the system reacts very good and is very stable and controllable even with wind.


Next step will be to remove the clevis in the commands because the system could maybe accept a direct servo in the roll and pitch plates and take advantage of a larger roll and pitch travel (-45°, +45° for ex) and more room in the frame (or a lighter one). CC3D will be replaced by a SP racing F3.

Thanks for your comments if you have!

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  • what is the total weight and the battery package of the system ?

  • nice place you have there
  • Yes and consequently a better efficiency but there is still a lot of work on the contra-rotating motor!

    inverted = not working, I stopped the tests after about 10 crashes:D


  • Impressive project.  Actually, since your concept is not so dependent on prop kinematics for stability, you should be able to swing a much larger prop diameter than a quad equivalent before stability goes to pot.

    Nice work!

    Can you get it to balance inverted...? :D

  • @John Arne Birkeland, thanks for the link, CR23L was amazing but with a weight of 300g, it's too big for me because I want to keep a "pocket" size. With these CR motors, your project was not a copter, it was a rocket!!!

    @John, thks,

    @Alex, the yaw is controled by the speed of upper and lower props to create a momentum. Of course you can use a PX4 which is an amazing FC.

  • Impressive work!! Thanks for the generous sharing.

    Two newbee questions:

    1. How to change the heading of the camera (I think the CR motor keep constant zero yaw torque)?

    2. Not possible to use PX4 to replace the openpilot FC?



  • I like it, nice work.

  • Developer

    Never mind.. I just found the archive link. They are discontinued, and have a much higher KV (1100KV) then I remembered.. So no good for 15" after all. More like 12".

  • Developer

    Seeing this reminds me of an old abandoned project of mine using some larger coaxial low KV motors (up to 15" props) that would be perfect to make your setup more efficient (and also less noisy).

    Trying to find a link, but I bought them on HobbyKing years ago, and it seems they are discontinued... :/


  • @Romushok, thanks for the link, not easy!! that's more or less what i try to do with the antigravity 4004 with two ball-bearings. I have to test it now... many thanks!

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