tricopter on pixhawk?

  I've tried QGroundControl, APMPlanner and Mission Planner. Some of them show category of frame type like X or + config, But no way to say what type of frame more specifically then that. Thats confusing. Mission Planner allows me to specifically click on the tricopter icon, but I'm not sure its uploading the tricopter firmware. Only channels 1 and 2 do anything. Can someone confirm that the pixhawk can to tri? Not the Y6. Tricopter using 3 motors with the back motor connected to a tilt servo? If it is supported, Is there any documentation on how to set it up? Motor order, servo output? There seems to be no way to know what frame type is currently loaded in firmware. Is there a way to see this?

It feels like If I were doing a quad it would just work. I'm not sure where I am going wrong.

If anyone has any ideas please let me know, Thanks!

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  • Trying to set a tricoptor up with a pixhawk after 4 days still not getting it off the ground has any one a step by step guide, ive googled to try and get a solution but no joy.

    It is spinning on its skids when trying to take off yawing to the right  , I have tryed different firmware but no joy. I have reversed front right motor which has made it slightly better. I have firmware ver 3.2.1 y6a installed with 3 motor setup servo 1  pluged into channel 1  motor 2 plugged into channel  2 tail motor  pluged into channel 4 and tail servo into channel 7 I have reversed tail servo in software the only thing I went off track with is aileron channel was working in the oposite direction so I revesed it in the radio. all other channels are not reversed.

    • Same problem here, cant get the yaw servo to respond, if someone gets it right you would be my hero if you uploaded a video of how you did it. 

      I belive it to be the configuration in the apm or controler. 

      I have exactly the wiring you said, power from the bec and neutral with signal to the pixhawk. 

      Really my last step towards getting in the air, everything else is working perfectly fine. 

      • Ill try and point you in right direction, I watched you tube video saying you have to reverse servo in the software not on the radio. So been trying other things thinking is firmware for right frame wiring etc motor direction right . Then I reversed tail servo in radio and abra cadbra it worked.  So remember tail spins counter clockwise so air is pushed down. But also take props off and see if gyro is going the right way as it has to push opopsite to the tail direction. IE when you  push tail right the moter should tilt left. With no inputs from radio then when left rudder stick is used the moter should tilt right.

        Is you servo dead IE no response the signal wire is at the bottom of the unit not the top like recievers live in midle and negative at the top. Also servo only works when armed and motors spooled up on fast idle.

        • Hi all

          When connecting an ESC to power the output rail is it still necessary to use a 5.7v diode as mentioned in the instruction or are esc's good at holding their voyages steady so making the diode unnecessary.



  • i have the problem too the tali servo is not responsive i don't know what is the problem and it will right and lift in the yaw pleez help  

  • HI guys, I too have a Pixhawk on a Fortis Titan, Alhamdulillah no issues, and one of my friends has it an APM 2.6. Since a recent rebuild, after a crash due to prop failure. Now we notice, which may have been there before, a constant oscillation, like a wagging tail, it happens the moment the motors start spooling until the end of the flight.

    Any ideas guys, we have looked though and tried changing parameters, all params related to yaw, with no luck.

    Thank you for any and all help :-)

    (logs and params below)


    2015-02-03 18-19-35.tlog

  • Okay I got it. Here is what you do!

    1. Follow this link and you will see the tricopter selection.

    2. Follow this link and scroll to the bottom of the page and see the tricopter setup and wiring.

    3. Look at the main output that are labeled 1-8 on your pixhawk. Use 1, 2, and 3 for your signal wire for each esc. Now plug your servo signal wire only into number seven. Make sure you power wire "red and black" are disconnected from the servo connector that goes to number 7. Power the servo directly from a SBEC or BEC. The power rail "positive pins" are not powered. Your servo will do nothing. 

    That should do it. Keep in mind you don't need the red and black on each servo wire from each esc. You just need the signal wire. Try this and let me know how you do. You should be good.

    • A few comments on this.....

      Tricopters use outputs 1, 2, and 4 for the motors (not 1,2,3), and 7 for the servo.

      With Pixhawks it's really a bad idea to use just only the signal wire to control the ESCs. You should also include the ground wire from each ESC. There have been extensive discussions of this and using ground wires is the current Dev recommendation. With APM's it was possible to get away with this, but less so with a Pixhawk. It's a risky proposition and whether or not it works depends on what model ESC you have. But using a signal wire only for the ESCs is not recommended for Pixhawks.

      Finally, there's no reason you can't use one of the BECs from one of the three ESCs to power your output rail and single servo (assuming you're powering the Pixhawk via the Power Module). You don't need a separate BEC to do that. I usually power mine from the tail ESC, plugging in all three ESC wires to the output rail. Of course this won't work if you're using Afro ESCs which only have about a 500 mA BEC. That's not enough to run a servo. If you use ESCs like these, you would need a separate BEC.

      • I'm running or going to run turnigy plush-40a esc's on a tricopter with the Pixhawk powered from the power module. Will I be OK using the above setup. Is there any heat issues. 

        • Just mentioning you are using 40 Amp ESCs and no other info makes it hard to say if it's OK, but generally 40 Amp ESCs should be fine for most tricopters. And you know you should only plug in ONE of the three ESC 5 volt power feeds to the rail to power your servo (NOT all three 5 volt leads)? Shouldn't be any heat issues unless you are doing something weird with the ESCs or using them to power other very big items on the tricopter.

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