What parameters are needed to make 3 motors tilt on a tricopter

Trying to develop what Kris made here… he has published his parameters but I cant get them to work… Im using a pixhawk4.
any ideas would be appreciated.


Can you detail the problem? What doesn’t work exactly? I think Kris had provided custom firmware along with the parameters. May be that’s your issue…

Hi Albcem, thanks for the reply… I initially tried using the Px4 flavor of firmware (using the “convergence” firmware on QGroundcontrol) and the plane went into a flat spin and crashed (there were other factors that Im working on),

Since I saw Kris flying using arduplane, I have been attempting to use his firmware (which I think is running chibiOS) but the control assignment for the rear motor tilt are not showing up in the available list. Everything else looks OK.

  • I have loaded his latest firmware (july 2019)
    -I have loaded his “Y-3x3” parameters

I have not had a chance to test this as operational but was hoping to meet up with someone who has played with Kris’s firmware or can show me how to open up his firmware and check the assignments.



I’m fairly sure the Arduplane stable release will do this, only thing you will loose is the ability to pick to use only the centre or only the rear motor in forward flight.

I also think it is a safer bet to go with the standard firmware with the open source which you may be able to modify to do what you exactly want.

Firmware from Kris, will not let you do that. However, if you want to test things out with this firmware, here is what I recommend you to try: Match the firmware release date to the date of the parameter file (which is October 5th, 2018) to ensure that the parameter file is compatible with the firmware released. It is very common for programmers to break things and not maintain back compatibility with new releases…

If you get things to work, please let me know - I am curious about it!

Hi Peter and thanks for the response… If I could use the stable release that would be great (although it seems that ChibiOS made the PX4 run better).
Peter, would I select the “motor tilt” option? (which is #41 in the options). I would not need to use just the aft motor for propulsion. Also do you have any tips for selecting the frame types? There is no direct option for what I have…

the frame setup I am using is as follows;
Q Frame class - 7
Q frame type - 1
Q tilt mask - 11 (This eliminates the front motor in a “plus” prop configuration).
Q tilt type - 2

Albcem - Thanks for the info… I wonder if the different param file would do that…

my big issue is that Kris calls for option “45”, which is “tilt motor rear” by him but does not show up in the options list in his firmware… But, the firmware does show option #41 as “motor tilt” but I dont know how that would behave. I need it to handle pitch while the front 2 motors handle Yaw.

thanks for the help!


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that all seems fine, for the front tilts you would use tiltMotorLeft (75) and tiltMotorRight (76) the center/rear tilt would be MotorTilt (41)

OK, got everything hooked up and was able to arm the pixhawk but nothing worked correctly. Im going to have to check my pinouts and servo assignments.
the pinout map I used was from Kris’s firmware… I wonder if that is a lot different from the stable firmware?

Still having problems getting the servos and motors to behave the way they should. motors are operating, but with no logical method. the elevon servos sometimes work but none of the tilt servos are working at all (in any axis of movement).

Im in Q Stab and stab.

is your Q_TILT_YAW_ANGLE set? you could be stuck in Q asist, it wont switch from hover to forward flight until you reach your min airspeed, for testing on the brench you can switch to manual first, ie Qstab -> maunal -> FBWA

Ok well Ive tried to get the tilt servos to work with no success at all (they dont do anything). The elevons work but only in FBWA and only by moving the throttle (lol). This is with the stable aurdupilot firmware.

I installed the convergence firmware from px4 and the motors and servos worked they way they are supposed to.

Im dumbfounded why nothing is working at is should on the arupilot build.

any ideas?

It’s normal, it’s a firmware behaviour when moving throttle up, it adjusts pitch.

So why not moving even in fbwa without remote control ? May be basic like safety switch ?

the odd thing about the elevons/throttle movement in FBWA is the elevons move opposite (roll axis).
there is a hardware safety switch that i am using. another odd behavior is the motors keep spinning after the plane is disarmed… the safety switch shuts them off… weird.

Im going to try loading default params and see if I can build the basic attributes from scratch.

thanks for the help

Well I again tried to use ardupilot on my pixhawk4 and nothing works at all.

at this point i have to question the dev team and if they are capable of making this firmware function for a VTOL. Anyone can make code for a standard airplaneor quad.

This is extremely dissapointing and the truly sad thing is Kris (whoever he is) has made all 3 motors tilt and it worked very well.

Does anyone from the dev team ever look at these forums?

is there ANY way of talking to a dev?

I mean what is the point of trying to build a plane if the dev team has to hide in the shadows sucking their thumbs and NEVER EVER HELPING any of the plane builders.

I seriously have wasted about 200 hours of my time JUST working on the software portion of this VTOL project. My plane is designed to be a serious plane… it is made of carbon fiber wings and CF CNC parts (I have built a CNC for this plane).
I am a serious builder and am COMPLETELY hobbled by these ass-fart devs that dont know and dont care.

But I guess expressing my frustration is lost in the wind of pig vomit that is ardupilot.

thanks anyway guys

er, I’m a dev and I was advising you

As I’m sure you can see around the forum plenty of people have great success building VTOL’s. It is not necessarily easy to get into how it all works but it can be done. I’m sure you appreciate that both the ArduPilot code and help here on the forum is provided on the free.

There is a wealth of information on the wiki or you can ask polity here on the forum and users and devs will do there best to advise you.

If this is not good enough there you can get commercial support, maybe you could find a experienced user or dev near by to help you get setup.

Well, I’m not a developer but I use arduplane since fw 3.4. IMO Ardupilot is less intuitive than px4 with crap GCS (windows like technos, organisation and minding for an opensource fw is totally bad ending).
Did you ever try to make a standard arduplane build ?

If Servo move the opposite way, it’s documented here :http://ardupilot.org/plane/docs/servo-functions.html?highlight=SERVOn_REVERSED
So you have to adjust/play with SERVOn_REVERSED. When everything will be ok (moving plane up/down and left/right control elevons correctly in FBWA), you could adjust your radio control parameters.
If the control are reversed with your RC you have to change RCn_REVERSED : http://ardupilot.org/plane/docs/rc-throw-trim.html?highlight=RCn_REVERSED

For people who want to follow this discussion, author duplicate it here : Are there any actual devs in this forum?