Skywalker X6 Vtol Quadplane nose-dives in fbwa

PX4 Autopilot VTOL 🚁
1

hi,
im new to VTOLs but i have some experience in px4.
I tried to setup a quadplane with x6 delta, 4x multistar 3508 700kv with 60 Amp HK escs.
worked well in Qhover mode but after transitioning to FBWA it just nosedived a couple of time. i am using GPS only, no airspeed sensor right now.
not knowing whats happeninng i disabled the quad mode and removed the quad motors and frame and tried to fly it in fbwa mode. it again nose dived rolling.
tested a couple more times and everytime it happens…
someone please identify the problem or what im missing.
here is the log file

Thanks
Basit

2

Hi Basit,

You are using APM and not PX4.
This discussion forum only deals with PX4.

Please refer to the APM forums or give PX4 a try, that supports delta vtol’s out of the box.

3

@sanderux im using a Pixhawk
how did you infer im using an APM?

DSC_0953.JPG3264×2448 2.19 MB

4

PX4 does not have Qhover flight mode, also your log file is in APM format.
Based on the fact that you sent a picture it seems you are referring to the Flight Controller hardware. I understand this is confusing.

The hardware (a pixhawk in this case) has 2 logo’s on it; APM and PX4.
The software running on this hardware (compare it to the operating system on your computer) can be either APM or PX4.

To install APM you normally use mission planner or apm planner. To install PX4 you normally use Qgroundcontrol.

5

yes after you mentioned i figured out mission planner by default installs apm based firmwares. i am now configuring my plane in QGC.
i set it to skywalker x5 as x6 wasnt there.
i hope it goes well with this.

Thanks

6

for VTOL i would suggest you use Generic vtol delta

7

i’ll start with the fixed wing config, test and varify it as most of the guys recommend. after that i’ll put my quad motors on it.
QGC is a litlle bit non-user friendly for me
cant find the parameter that changes the servo outputs

8

Search for PWM_MAIN
You will get PWM_MAINx_REV to set

9

Also note that when you switch to VTOL your outputs change.
On a quad delta its:
MAIN 1234 = quad motors
AUX 1: left aileron
AUX 2: right aileron
AUX 3: pusher motor

10

and for a conventional pusher they are all on MAIN 123?
1 and 2 for ailevons and 3 for pusher?

11

3 is unused
It’s 1/2 for elevons, 4 for pusher

12

cant find the parameter to get my aelvons right from QGC and neighter my pusher turning…
please help

13

Pusher turning you can control by swapping any 2 of the 3 wires from your pusher esc to your motor.
setting PWM_MAIN1_REV and/or PWM_MAIN2_REV to 1 should reverse the output on your ailerons