Hi Mitchell,
Looks like you have uploaded the wrong log.
In this log all I can see is your plane sitting on the ground near the edge of your flying field.
[quote=“Pieter”]Hi Mitchell,
Looks like you have uploaded the wrong log.
In this log all I can see is your plane sitting on the ground near the edge of your flying field.[/quote]
It is the correct one, i pick up the plane at 41%.
And yes i had no gps fix, just wanted to do a manual test flight.
Flight lasted only 10-12 seconds.
Damn… i just notice that it went into RTL after the first right turn…
Can anyone see why ?
[quote=“Mitchell”]
And yes i had no gps fix, just wanted to do a manual test flight.
Flight lasted only 10-12 seconds.
Damn… i just notice that it went into RTL after the first right turn…
Can anyone see why ?[/quote]
Yes I can see it now. Things got bad when you hit RTL without GPS lock.
I believe the GPS is used to correct the IMU from getting weird in tight turns, so when you hit RTL without GPS I can imagine that your plane tried to correct itself from a faulty attitude reading. (at least, with the old APM 2.5 hardware that used to be an issue, dont know about pixhawk)
But why did it hit RTL?
I’ll take a better look tonight.
[quote=“Pieter”][quote=“Mitchell”]
And yes i had no gps fix, just wanted to do a manual test flight.
Flight lasted only 10-12 seconds.
Damn… i just notice that it went into RTL after the first right turn…
Can anyone see why ?[/quote]
Yes I can see it now. Things got bad when you hit RTL without GPS lock.
I believe the GPS is used to correct the IMU from getting weird in tight turns, so when you hit RTL without GPS I can imagine that your plane tried to correct itself from a faulty attitude reading. (at least, with the old APM 2.5 hardware that used to be an issue, dont know about pixhawk)
But why did it hit RTL?
I’ll take a better look tonight.[/quote]
Yes, that’s the question.
The plane was 20 meters away from me so a real receiver failsafe is unlikely.
And i certainly did NOT put it in RTL haha.
The weirdest thing is that when i retreived the plane the elevon’s only moved a few mm’s …
I then connected the elevon directly to the receiver and it looked good, then back on to the APM and again the movement was not ok, very small movement.
When i came home i updated the APM and the elevon problem disappeared.
So this got to be a software/firmware issue in my opinion.
Oh and i use a APM 2.6
I don’t think this is a firmware/APM related issue.
See the screenshot I attached, of a TLOG graph I made from your LOG.
(I’d rather have dataflash logs to analyse, the TLOGS give me headaches)
The light blue line is your raw input of your mode switch channel. You configured ch8 to behave as your mode switch. Most of the time it is all the way up to 1738 PWM value, which correspond to FLTMODE 5. You assigned FLTMODE 5 to manual. So far so good.
All of the sudden the PWM value of channel 8 drops all the way down to 1199 (FLTMODE 1), and you set that mode to RTL. ( plane.ardupilot.com/wiki/ardupla … fltmode_ch )
Then your plane tries to navigate to somewhere without GPS and without correct attitude (because the lack of GPS) the blue line in the graph is where the NAV controller becomes active, and a crash becomes unavoidable.
Perhaps you’ve accidentaly bumped your mode switch? or a wire has gotten loose somehow? What kind of RC equipment do you use? maybe it really was a receiver glitch/failsafe, that explains the sudden short drop of throttle to zero at the time of the switch (green line)
please next time you go out flying, make sure you have good GPS lock (HDOP <2) before takeoff. I usually connect the battery and let it sit for 5-10 mins.
I recommend using a pre-flight checklist or something like that.
Thnx for looking into it!
That throttle drop at the same time as mode switch is weird indeed.
Looks like real receiver failsafe.
I build the apm into another plane with another receiver and will test it today.
I use an Futaba t7c with frsky receivers, i have reached 1200 meters with this setup on my quad
This time i will wait for gps 
Ok, tested today.
Everything worked OK!
Hopefully it keeps that way.
However, when i i try to download the data flash logs i get an error : Error receiving log list…