"Try this methode, it works verry well without risk and is rapid.
https://www.youtube.com/watch?v=aq1jXHMiJgg&feature=youtu.be"

"@Rod Davis,
- Can you check the S-Bus Signal with a Scope? The Signal high should have around 3V.
- Perhaps an interfearing with the AUAV WLan Modul and TX. eg. it was recommended to switch of the wireless connection of   the Gopro.

Or both…"

"Rod Davis said:
I wasn’t sure if I should be posting it here or over in the discuss.ardupilot.org site.  I’m having trouble with radio timeouts between a D4R-II and Pixracer. This has been an ongoing intermittent issue.
I have tested with and…"

"Never ending Autotune,
As with 3.4-rc1 also 3.4-rc2 never ends the autotuning within 7 min and for Roll only.
And as I could see in the log, the values for P and D are decreased from the manual setup with good attitude below the defaults.
With the…"

"Never ending Autotune,
As with 3.4-rc1 also 3.4-rc2 never ends the autotuning within 7 min and for Roll only.
And as I could see in the log, the values for P and D are decreased from the manual setup with good attitude below the defaults.
With the…"

"The PX4Lite gold has also a metal case and works well.
Perhaps negativ the weight or positiv because of dampening and crashproof.

Now, you will have to learn soldering. I assume, there are no suitable cable.

I had 4 weeks trouble to tune Pixracer.…"

"When I ordered my Pixracer in Feb. ist was delivere mid March.(6 weeks)
Depends on  production lots. Marcell Kovacs said:
How many days was to get your pixracer shipped from AUAV? Mine is processing for more than a week now :( 
And I get no…"

"@Denis,
The description (5V,SCL,SDA,GND) ist a I2C Port on Pixhawk 4 pins, The GPS is connected to a serial Port (RX,TX) on Pixhawk or Pixracer 6 pins. On Pixracer the GPS Port is combined with RX/TX and SCL,SDA on a 6 pin connector.

Denis…"

"Not for me and many other.
e.g. In AltHld the altitude varies +/- some Meters
       Within 3 mins the Hexa sinks continuesly in AldHld
       After landing the Altitude shows 5m, after arming 0m.
       Autotuning does not work (No reaction)
     …"

"Hi Cala,
The same with my Frame F550, Mots 2212/920 (original DJI) 1.8 kg
Hoover with 45%
Has nothing to do with oneshot or hight kv motors.
I will post it on the recommended link.
Otto"

"@Hugues,
....Ardupilot has not been designed with FPV racing.....
Do you mean, in this case Ardupilot ist not usefull for the PixRacer?"

"Another 2 Pics
Pixracer left.jpgPixracer right.jpg"

"Hi Cala,
Verry kind for helping.
Attached the Telemetry Log, and the Dataflash Log.
1 Pic of the setup.(2 Pics in the following message)
The Pixracer is under the blue cover, Baro with foam underneath.
In the Telemetry Log you can see the dancing…"

"Hi Cala,
Thank you for your help.
No, no turns.
I startet egain from the verry Beginning. Flashing, Params reset to default, calibrating TX, compass and Accel.
And then tuned to the PID like bevor with Pixhawk.
But the same behavior. In AltHld…"

"Hi Marcell,
Thanks for your answer.
I will try it. This calibration ist difficult, because during calibrating, several messages (about missing GPS, which are not of interrest at this time) disturb/ interrupts the process. I had to restart many time."

"With MP Beta it was possible to increase the Params.

But now with the same Params and Frame as with Pixhawk and FW 3.3.3, the behavior is verry strange in Loiter Mode.
Even with 9 Sats and hdop 0.9 it moves around slowly in a range of 10 m, +/- 5m…"