First post : )
I have had my new 3DR Quad-D with APM Mega 2.6 for about 10 days and have had an issue almost every time where the APM goes into "land" within about 15 seconds of liftoff. It is January here and I keep the LiPos in the cold cold garage. Perhaps they need a warmup? In flight, a quick switch from Stabilize to Loiter and back to STAB seems to clear the issue for the remainder of the flight.
Here's my relevant configuration-
Frame: 3D Robotics Quad-D
FCU: Ardupilot Mega 2.6 w/ GPS and Compass
Power Module: 3DR APM PM
Batt: 3S 5000 mAh. **5 years old. Balanced weekly. Lasts about 3700mAh
ESC: (4) 3DR 20A
Motor: (4) AC2836-358 880kV
Prop: (4) APC 11x4.7SF(P)
RC: FlySky FS-TH9x, FlySky D4R-II RX
Telemetry used for Minim OSD and AndroCopter via 915MHz radio modem
Sounds like battery failsafe is kicking in, but the only way to tell for sure is if you clear your flight logs, do a fligt, then post the dataflash log so we can see exactly what is going on.
Thanks Wessie. I'll try that. I need to learn all the features !
I will say that I did a static RPM, volt and current test where the airframe was attached to a piece of plywood- and it still manifested the same problem.
No worries, if you don't know how to do any of the things I said, say so, and I will give you step by step instructions.
Just saw that your battery is 5 years old. Think we have just found the likely candidate.
If you can, try with a new(er) battery and let us know