Discussions

I did the maiden flight this evening with the APM. I’m using ArduPilotMega 1.02 version dated 10 Jan’11. I have MTK GPS module configured with GPS_PROTOCOL_MTK (not MTK16). I followed all the protocol and everything seems to work OK. The start up sequence works fine, GPS locked, HappyKillmore GCS show right GPS location and attitude of the model, on ground “Stabilize” mode test  look fine, banking and pitching the model the surfaces moves in the right direction. So, “Manual” mode and take off. After a couple of minutes in Manual to trim and check that everything is OK I switched to “Stabilize” and… “ups!”.. the model pitched down hard. I had to give full stick up to fight against the APM that tried to put the model direct on the ground. After landing, I reduced SERVO_PITCH_P and tacked off again. The behavior in “Stabilize” is erratic, some time pitched down, sometime pitched up, and the most stable I got switchin to STAB was the model rolling to inverted and flying in this position. Yes, you understood well, stable flight but inverted. I ordered today the Xbee down link and next weekend will try again but with telemetry to see what it is going on onboard. Somebody has an  idea? What can be wrong?

I need help!!