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
There are several known states on which motor/throttle movement can occur w/o arming/throttle input, mainly when the APM gets reset during a USB connect while the LiPo is connected. I also experienced a different issue following a minor crash on my first flight day (flipped unexpectedly while 90' away, after my best first flight, head down) When I got to it, disarmed, flipped it back over, then re-armed, only one motor spun. So I disarmed, maybe 10 seconds, a long time because it was hard to see the green blinky. I looked right at the blinking green light, and took my and off the throttle, and the opposite motor from the working one hit 100%. Nothing stopped it but holding the trottle hard left/down. No matter what I did, that motor spun unless I held hard left/down. Disarmed. I looked at the flashing green light and had a buddy look at it to be sure I was not crazy. But that is not the fun part.
After retrieving the quad, disassembling and re-assembling the APM rail cabling, and verifying settings on the ESCs, and swapping batteries, I had the transmitter 10 feet away and safe/throttle off, I plugged in the battery and immediately props spun hard. I kicked the quad away out of reflex (it was straddling me and I, it, it is a big beastie) and I lost only a prop.
My crash did something to that quad that day. I still don't understand what. But I learned to respect the danger, and not to trust in just the radio handling.
Just a thought, dont know if it will work for a quad but with my heli i always set throttle hold at 0% so even if i hit the throttle nothing happens until i move the switch.
I dont bother taking mine off, I keep it clear and I velcro strap it down...so it wont go anywhere!
You are quite a Wounded Man. http://en.wikipedia.org/wiki/Wound_Man
I am not sure if I would do such.
You are a great explorer Such as Byrd, Scott, and Almundsen.
Ouch! Hope you feel better soon. May the helicopter gods accept your blood sacrifice...
Seriously, thanks for being brave enough to post about your "dumb move" so the rest of us (err, rest of them...) can learn from the mistake and see why all copters should carry a government health warning,
Yikes, I hope it heals soon for you. Thank you for the invaluable reminder.
Ouch! Be sure and post your picture in this thread on rcgroups:
Yes, the arducopter can be a nasty beast. Earlier this summer, I fired up mine in the garden, with one of those 3x firmware versions, chopped down a bunch of my wifes plants on the way down. Consequence; very nasty. Really not to be mentioned at a public forum. (Denial of access to benefits previously granted on a regular basis, and so on).
Just to add to the disconnect-motor before testing... I was testing an Ardu-variant on my R/C buggy and of course, had grown complacent with correct function and start-up. Something went wrong, the motor went full throttle on start-up, and I instinctively grabbed for the car. Well, I grabbed right near the gearbox which I had recently removed the cover from and got a nice little gouge to one of my fingers. Not quite as severe, but lesson learned.