Dual-motor tailsitters

Don’t have that kind of devices at all :frowning:

It’s a must have ! You need this …

Turns out that i have a friend who can borrow that.

But what info or where i need to look exactly, how this can help me. Sorry, I just heard 3DR 20 minutes ago :slight_smile:

Thanks guys:)

your log are impossible to analyse for me as they are quite long, about halt an hour for the first one, with continuous switching from manual to q_hover. I hope you dont try to fly manual as this is impossible even you are the best pilot of the world.
I have found that you have disabled arming check. So the pixhawk allow to arm and take off even in the worst case. You should not do that. You definitively need the telemetry link with the 3DR radio, it will give you real time health status of EKF, gyros, compasses…

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Telemetry radio inform you in real time what is wrong or what is good. You could monitor sensors in flight with GCS to show if something is wrong or not instead of flying then watching logs.
For example, like losawing say, you have disable arming check, if you had telemetry you will know why you could not arm but this option need to be enable.

I’m not a developer, just watching this thread by curiosity, but there is some basics for ardupilot fw. May be it’s not a good idea to start with tailsitters and hope you will fly it in the proper way one day.

I push the manual if my plane goes crazy, then i can control my plane again, when plane is wired up and can’t fell on the ground. That’s why i only use manual mode

Regards

@TopGun17 It looks like your pitch P gain is too high in log 101, since you’re getting large oscillations.

Hello I have a question regarding fixed wing logic. I am trying to understand how quadplane.cpp works to be able made some changes. There is a few comments referencing “fw controller” but i was not able to find where is this control for fixed wing modes like FBWA implemented. Can anybody give me some clue? When I looked into quadplane.cpp I can not see any logic for FBWA. Especially I am looking for a place where the servos output for motors is being set. I tough that it is within AP_MotorsTailsitter.cpp but it seems that AP_MotorsTailsitter::output_to_motors() is only for VTOL modes. I will be glad for any clue.

Look at library APM_Control. There are separate controllers for roll, pitch and yaw.

Quess what, my plane can hoover and fly :smiley: At the end i broke my plastic servo but ti worked very well :slight_smile:
Nice, thanks all for your help (Y) Adding video later.

I have question, because it broke down a little bit and i need to have new foamboard, where i can find aileron mixers?
Because now i would like to build almost same, but with rudder and elevator? Where i have to make changes to get those also work?

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congratulations. Just to know, what improvement did you implement ?
I don’t understand your question. But when I checked your parameters I saw you have set servo1-function and servo2_function to 77 and 78 which is correct to get elevator and aileron mixing.

Actually my P was too high and i guess the main reason why it didnt hover like i wanted was wrong CG :smiley:

But my guestion is what i do when i add also rudder? What output i have to connect my servo? Where i can find a mixer that my rudder also starts to work like i want :slight_smile:

I try to build tailsitter fuction to a regular plane, at first also two engine to both wing. But i dont know how to put to work elevon and rudder that way that hover also works.

Regards

Rudder function of a dual motor tailsitter is obtained by differential thrust in both VTOL and fixed wing flight. There is a parameter rudd_dt_gain to adjust the amount of differential thrust in fixed wing. But if you want to add a vertical stabilizer with a control surface you simply have to connect a servo to an output and set it to 21.
This is a strange idea to make a tailsitter with a regular plane but the method is always the same, connect a servo and set the output as you wish.

Here is the hardware for my vectored thrust twin tailsitter. I’m requesting suggestions and/or criticisms.


Please- throw rocks at the design, but not the cats.
This is the third incarnation for this airframe- hovered fairly well as a tailsitter with OAVTOL and a KK2.1.5 board.
The concept has been mentioned here before, of having two lifting motors (bzucak et al) and a more efficient pusher. It seems like the next logical step in development.
The lifters produce about enough thrust with a full battery to lift the airframe- 3 kilos- and with the assist of the main motor, will not be overtaxed, but must run hard enough to offer good control-70% or so during the multicopter phase , perhaps. They will shut down and props will fold in FW flight.
I’ve read the whole thread and taken notes, so I know something about what’s been done so far.
My own observations:

  • if I had it to do over, I’d put the motors a bit farther apart. Too late. But the photo angle makes them look closer than they really are.
  • It will Need the full complement of vectored thrust twin control features, plus some provision to control the pusher motor and shut down the small lifter-stabilizer motors. Can this be done without new code?
    I am asking for constructive criticism, and some advice on initial parameters.
    Thanks in advance
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@losawing I just pushed a bugfix to my quad tailsitter PR branch: https://github.com/ArduPilot/ardupilot/pull/8113
I had the top and bottom motors swapped due to a sign error in the VTOL mode pitch control. Sorry if that’s caused as much confusion for you as it has for me :slight_smile:

I also added differential thrust for the top and bottom motors to aid pitch control in forward flight.

Nice looking wing; is that a custom build?
I think code changes would be necessary in AP_MotorsTailsitter to support your booster motor and shut down the other two. Are you able to modify the code yourself? I’m doing similar things in my quad tailsitter branch: https://github.com/ArduPilot/ardupilot/pull/8113

It’s an uncrashable Phantom FX61 modded in tail sitter !
@wazoo22 I have the same wing and same blue except th hatch kept in black

My wing is already modified but I need to compile the code again and I am facing an error related to flash memory overflowed. I make some search and found I have to remove modules. Now I have to figure how to do that. This is a little frustrating so if I do not succeed shortly, I will ask your help.

This is the full parameter list of my vectored bellysitter wing. It fly pretty well with those parameters even with some wind
blue wing 21 avril.param (16.3 KB)
probably the most critical is the back transition. Important parameters are Q_m_spin_min, q_m_thst_hover and q_velz_max < 100cm/s. For the beginning, use Q_hover and FBWA modes. Q_stabilize is dangerous and Q_loiter less stable.
You say your wing motors produce enough thrust to lift the wing (just enough ?) . I found that with powerful motors and vector thrust the wing can recover from the worst situation. This is something to consider at least during the tests.

Yes, it’s a custom build, using parts of the FX-61 phantom, lightly glassed and reinforced.
Unfortunately, I’m not a coder. Slugging my way through “Arduino for dummies”, if that tells you anything.:grimacing:
I’ve followed your ideas, but don’t understand the airframe layout you intend to build once simulation is played out. But I’m interested.