Or an autopilot in this case. Something went wrong with the ArduPilot and the AXN Floater dived into the ground from about 50m up.
First, some nice photos from the day, which had perfect flying conditions:
And a video of a couple of ArduPilot stabilised glides down from about 170m. The glide ratio is about 10%, covering 1200-1500m.
Altitude profile of the last flight:
Overall, the AXN Floater was a great plane, I flew it for 2 months getting about 26 sessions and 7 hours of logged flight time. It took about 1 hour of flying over 5 sessions to learn as I was starting from nothing and didn't have anyone to show me the ropes (a bit stupid really, but the plane survived a couple of rebuilds and replaced servos). The eventual battery life was between 15 and 25 minutes (from a 2200mAh 3S LiPo) and it was covering about 15km distance along the ground in a session.
The maximum altitude I flew to was probably about 200m (I logged 183m with the ArduPilot on board) and the cruising speeds were between 30-70km/h on average.
I've no idea what caused the crash, I had some issues while attempting to test the Loiter and RTL modes, but was able to recover from those. At the time of the crash it was flying fairly quickly (throttle nearly wide open) and there was a bit of a wobble/turbulence, then it just turned and dived:
The fuselage was very damaged, broken in a few places including the motor pod, but the wings are salvagable. The main thing stopping me bothering to repair it (for now) is that the receiver antenna was cut (even though I hot-glued it), and since it's a coaxial cable, it's going to be pretty impossible to repair and still guarantee a decent range.
The ArduPilot was protected well by it's pod, though the GPS socket was ripped from the ArduPilot board. Thankfully there are through-the-board holes I can solder it back on to later.
Time to get serious with the QuadCopter now!