Hi All

    I have just had my first day of successful Flying on the Bixler2 with the APM2.5+ with Firmware 2.70 on it.  Other hardware on the plane was the RFD 900 telemetry, ASI, a 9x5 prop, 3530 out-runner, and an aluminium motor mount.

Flight 1, started the aircraft 100m off the tree line, just in case.... set RTL Altitude at 50m.

started in manual, took off, and trimmed the aircraft.  I switched it to stabilize and it entered a dutch roll, that was so violent that it threw out the battery :)  fortunately, without the battery, the aircraft floated to the ground perfectly flat, no damage.

after spending an hour looking for the battery.... adjusted the gains on the pitch down a LOT.

Flight 2.  Plane flew well, stabilize is still a bit touchy, but acceptable, RTL tested well, and then tested loiter, all good.  Auto mode, the flight path appeared to be 100 meters to the north of where I had programmed it, but it flew it well.

Back to stabilize  and I forced it into some horrible flight attitudes, let go of the sticks, and it instantly recovered... very nice, until...

the engine stopped, then the plane fell with no control and smashed into the ground.

other than the front of the plane smashing up (nothing hot melt and more tape couldn't fix) I couldn't find any faults, but noticed that one of the esc wires to the motor had unplugged...

OK, that explains the motor stopping, but why the lack of control?  normally here you would glide to the ground and do some walking :)

my question... is it possible that while the wire was partially connected, that the electrical noise caused the APM to re-set?

any suggestions?  how do I get the data-log out to post here?

Just to confirm, I have since flown the repaired aircraft, minus Telemetry and GPS, and the stabilize mode is all good. 

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Not sure why you would have lost control.

I would always recommend a separate BEC however.

Do you have any telemetry logs?

Not sure, need to figure out where the logs save
It has a separate BEC for the servos, the APM is powered via the power monitor pcb.

It may be the disconnected cable happened in the crash, I will extract the logs and see

Here is the log file, it just stops dead, looks like a total failure

in the Log, there are two flights, it gets interesting after 94%



Your log is quite unusual compared to my logs.

There are quite a lot of mode changes.

Also your plane looks to be flying sideways quite often.

Just before the end of the log the HUD shows the plane rolled twice.

Did that actually happen?

Yep, it rolled twice, that was intentional, this was an intentionally abusive flight, in very strong wind, up till the point it shut down, I was VERY impressed with the APM.
The rolls were testing for a new airframe we are designing, I need to know what went wrong, as I am currently building a fleet of UAVs for a UAV training school :)
Hmmm well unless the battery had disconnected it should not be power, since the APM is boardpowered. Did you have receiver failsafe set? Did it just go 'dead' and fall out or do you think anything was active?
Sounds to me like the APM which is the last in line before esc/servos would be the likely culprit, but it might not be that simple, trying to think of what else could have caused the behavior other than shorting the battery which you should see other issues with.
That was my thought, but all was still connected after impact including the battery, I checked it all back at the launch site, but other than the antenna broken off the telemetry (from impact) and the esc wire disconnected. At the point of failure it just died, no sign of life, fail safe was programmed as rtl. Was not good watching it fall :(
This is what I am hopeing, I am planning on soldering these connections before further flight.

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