Costly and frustrating start to my foray into hexacopters....  a heap of parts for a 3DR Hexacopter arrived last Friday, including APM 2.5, 5000mah 4s lipo, sonar sensor, 3DR telemetry link, uBlox GPS and the kit 850Kv motors and 10" props.  Asembled and working for Sat morning, with a couple of test flights in the garden Sat evening.  All good at this stage, but a couple of the prop nuts span off causing some crashes into the hedges.  No damage, but did need a metal detector to find the missing bits.

As of Sunday, I switched all the prop nuts for nylocks and went for some higher altitude tests, tested RTL and loiter functions.

Stabilise test:

https://www.youtube.com/watch?v=f-9JV8qvOsQ&feature=g-upl

RTL test:

https://www.youtube.com/watch?v=mtlYYcI2dn4&feature=g-upl

Fast climb test:

https://i3.ytimg.com/vi/njhNUfK-BZE/mqdefault.jpg

Today the weather improved, and managed to nip out to a local abandoned airfield to test the telemetry link and the auto waypoint navigation.  All went well for about 30 sec, taking off smoothly to hover at 20m, then ascending to 50m for the next waypoint......  then disaster struck as I watched a prop flutter off into the distance, and the copter go into a terminal tumbling dive, crashing at high speed into a shallow bog! 

Suffice to say, it did not fair well - two motors sheared off the alu struts, four props shattered and the electronics stack shredded along with its protective foam cover....  not a pretty site.  Plus it was sat in about 5 inches of muddy water, covered in grass.  Dragged it out, removed the lipo and then trudged back to the car with my expensive armful of wreckage :(

So - the lesson - make sure your prop nuts are tight, very tight, and loctite'd and perhaps even lock-nutted!  Fortunately it didn't hit anyone on the way down, but there were some spectators nearby who almost cheered at the splash it made and then watched fascinated as I fished bitsout the bog.

Now to order some more bits....  hopefully mk2 will last longer than 4 days!