as you can see in video after i takeoff and get some distant i engage the RTL and it want back and circle above the home location so i was sour its work just fine . then i fly it again and engage RTL and it fly back home but it didn’t keep the altitude or the speed also increase the throttle to full as u can see and i don’t know way.
so any one can help me to analyze the problem and understand what cause it so we can avoid it in the future.
Difficult to say, do you have the dataflash log? The reason why the throttle increased is because it was losing altitude and was using throttle to try regain height. The compass problem was definately an issue, a Pixhawk using EKF would have handled this better. The compass of course must not be near any power wires otherwise the magnetic field generated will offset the compass.
as you can see in video after i takeoff and get some distant i engage the RTL and it want back and circle above the home location so i was sour its work just fine . then i fly it again and engage RTL and it fly back home but it didn’t keep the altitude or the speed also increase the throttle to full as u can see and i don’t know way.
so any one can help me to analyze the problem and understand what cause it so we can avoid it in the future.
thanks[/quote]
I notice the airspeed very rarely got over half the ground speed, flying away or
homeward bound, and as the aircraft seemed to be fighting a breeze it should, I would
have thought been equal at some stage. My Finnwing did the very same trick…
This is what I deduced
manual flight good all systems go …apart from the airspeed …low ?
Never mind change mode FBWA… ground speed up from 38 km to 85 km ???
throttle 90 + % ee gad… circle get hight alt. now 200 mts. OK time for RTH
Throttle 100% Diving at 12 m/s to reach 50 m RTH hight tail wind no hope of pulling out
oops. Cause: a semi blocked air speed tube.
While in manual / stabilise mode airspeed by- passed .
FBWA mode airspeed activated but still under control (sort of) …RTH airspeed requirement is top order but there isn’t any well ,very little , time to auto open the throttle to achieve the correct air speed .
Well you know the rest.
Your elevator TRIM (RC2_TRIM) was 1632. This means that the plane had to constantly put in up elevator to maintain altitude. You also had PTCH2SRV_MAX set to 1500 so your plane could only move the elevator 15 degrees at most. This combination means your plane had very little ability to pitch up and climb. I can see from the logs that towards the end of the flight the ailerons and rudder went up so I assume the plane had RTL’d to the home location and was starting to circle. As it banked over it also put in max elevator but it would of had little effect so the plane banked and went into the ground.
Also note that towards the end of your flight your battery did dip down to 21.2 volts which was just above your 21 volts failsafe setting - just mentioning it - it had no bearing on this.