Now let me start off with YES I have read the manual where they state millions of times disconnect the motors, or take off the props whenever you are making certain changes.
I would consider myself well-versed with the entire APM, but I have chosen in the past to not get into the discussions on the forums, which is likely to change.
So I haven't had any problems with the motors spinning up AT ALL during the initial setup phase for any of the distributions. I have been flying and setting up this quad since early July of this year, and trust me, I'm absolutely hooked. Today, however, was an entirely different story. I was having some problems with ALT_HOLD pulsing in the most recent release, so figured might as well test out 2.0.42 and see how that faired for me.
I loaded the code for 2.0.42 (through the arduino software, which I have lots of experience doing with other arduino projects in the past) and then opened GCS in order to do the initial setup of my Quad. Reset the thing fine, and moved onto my controller calibration (neglecting to take off the props, or disconnect the motors).
Here I pressed calibrate, and tried calibrating my radio, but nothing was showing up, weird. Hit save, and realized my controller was off, turned that on, and before I could even blink I heard the whirl of my quad taking off at 100% throttle. Still connected to my computer via USB, and without direction from me. Without even looking I reached my hand out to prevent liftoff, and, well, too late.
It took off in my living-room, tore through my hand, across my laptop, and ultimately smashed into the couch, still running.
Now keep in mind this was a custom build of mine (The original Aeroquad frame directions) with 350w 910kv Motors. A little overpowered to begin with:
So here are the results of me attempting to stop my quad from taking off in my living-room (WARNING: GRAPHIC):
This one sure goes down in my own record books as my most expensive whoops so far.
New MBP Screen
New MBP Keyboard
One Motor, 2 Props
Frame looks okay
APM Board got caught in my bloody crossfire, but cleaned it and should function fine.
12 Stitches and 3 hours in the hospital! Woooo!
Thankfully no tendon damage, but you can see a small portion of it on the left side of that open wound :)
So what did I learn from this:
Clearly my quad is not an indoor flyer
RTFM and Listen to it!
And props HURT.......BADLY