Servers by jDrones

Dual-motor tailsitters

( research air) #861

(Mathis) #864

currently i’m building a tailsitter. (with Apm 2.8, 2 Motors and 2 Flaps) My problem is that i can’t find any parameters with a Q_ at the beginning. Not even the Q_ENABLE paramter. Is there something i overlocked? I would be very thankful if anyone knows why i cant find those parameters. I have added a picture in which you can see that there are no parameters beginning with a Q. Btw. i’m new here and hope that i asked in the right category. I’m sorry if that’s not the case.


(David Kaden) #865

APM 2.8 is not supported since long time ago, so ur ending up old software. You need to get a newer FCU like PixHawk, Pixracer, PixFalcon etc

(Mathis) #866

OK thank you. I have just figured it out an hour ago or so. But nevertheless thank you a lot.

(David Kaden) #867

UPDATE: Tridge fixed the transition in AUTO mode: Plane 3.8.4 released

Thanks Tridge!

(Andrew) #872

Hello, I have built a non-vectored tailsitter wing. running pixhawk/gps V3.8.4 with a DX8 all Q_parameters are Enable.

My problem is it works fine in manual/FBWA mode but when I switch to QSTABILIZE I have no throttle input from the TX or FC

I am not sure if it needs GPS to work in QSTABILZE mode? I did have 6+ GPS
Param’s.param (16.1 KB)

(Rolf) #873

Hi Andrew,

change ARMING_REQUIRE to 1


(Andrew) #874

Thanks Rolf, I gave that a go.

Now I am stuck on - PreArm:Check mag Field
I have run back through compass calibration and also accel calibration but Check mag field appears. I have obtain declination box check and I have also tried to use onboard and external compass

Offsets X 160 Y -219 Z -8
MOT X0 Y0 Z0

( research air) #875

Hi Andrew02
sometimes I just run one compass at least to get it to arm while setting up ,I am interested in better solutions from pix experts as well

( research air) #876

Also…FYI… STM flight controller…

(David Kaden) #877

Anybody tried SITL with RF8 any the model of my tailsitter that Otto created?
I cant get it to hover at mid throttle in auto alt modes. Even in auto and RTL it will ascend when it wants to sink.

(letpi) #878

hello Andrew,
I had this message until I used the onboard calibration

You may use only the external compass but I think this is not the problem as the message you will get with 2 compass and a bad calibration is ‘inconsistent compasses’

Also, check you compass orientation. With a pixhawk, the correct compass orientation is 'rotation_none’
Have a look at the following link to check your compass setup and calibration. This is very important.

As a general rule, it is better to install the compass and GPS as far as possible from electro magnetic sources including power module, battery, ESC, motor, RX with telemetry, 3DR radio…

(Andrew) #879

Thanks everyone for your input,
I move the compass/GPS another 30mm away from magnetic sources as far as I could get it, performed another calibration and it works. Testing later today! I will let you know how I go.

(Andrew) #880

Ok Tried some testing this arvo with no luck. Takeoff pitch forward breaks prop, takeoff pitch rearwards breaks prop and so on.I did give it plenty of throttle for takeoff.

What I have. Tailsitter 2 motors (T motors 2814-770kv running 13x5 props) 2 elevons with pixhawk, looking from the rear the right motor spins clockwise left anticlockwise.
CG seems ok.
If I tilt right side down in STABILIZE MODE right motor spins up quicker to counteract. Tilt left side down left motor spins up quicker.
Is this correct? Q_FRAME_TYPE 0

left throttle on channel 3 and right throttle on channel 4
I Did have problems getting my DX8 setup the only way I could get surfaces to move in the correct direction was to use -WING:DAUL AIL- I could not get -WING:ELEVON- to work

Tailsitter.param (16.1 KB)

(Matthias Favrel) #881

Hi Andrew, can you do the same check as you did for motor, but for elevons ? For instance, tilt forward, what is the eleven reaction ? ( should be both up).
What is the total weight ? What is the max thrust of one motor with your prop ? (use a scale)
To me the props are looking big for those small motors, what battery are you using ?
Ps:any pictures, video will help :slight_smile:

(letpi) #882

I don’t understand what you tried to do with your DX8. But do not use your Tx to reverse a channel or to make elevon mixing.
You first have to understand if you have a configuration problem (reversed elevon, bad parameter…) or a PID tuning issue.
Some general advise:
Breaking propeller is very normal. if you succeed flying your tail sitter with less than a dozen of broken propeller you are better than me.
When switched to FBWA or Q_hover, elevons must react the right direction when you tilt the wing.
you must have a GPS 3D fix or the EKF does not work. Read post 65 from tridge.
You have to tune you PID and increase P terms as much as possible. Mixing_gain is also very important, increase it up to 1,2. In the post 832 I describe the method I used with success.
Without vector thrust, the max pitch angle the wing can recover from is very limited so I suggest to reduce Q_angle _Max to 20.
Q_Frame_type is not used for tail sitter
Read post 281 from Kd0aij to understand servo group and pwm output.

(tridge) #884

Hi everyone,
I just wanted to apologise for not answering posts the last few weeks. I’ve been deep in the ChibiOS port of ArduPilot, plus preparing for a couple of conferences.
I hope to start doing some catch up on this forum soon.
Cheers, Tridge

(Manta) #885

Hi @tridge where can we read more about this port or what it might mean for Ardupilot? Thanks.

( research air) #886

(Manta) #887

Thanks @tilt, I should’ve phrased myself better.
Wanted to know what it means when Ardupilot is ported to this OS as I’m not aware of boards we can use that are using this OS.

Hope this clears my question