Que

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Multi Rotor attack!
« on: January 26, 2017, 03:07:56 pm »
I was hoovering in my house a couple of nights ago (first mistake) when my quad got away from me. I had enabled no motor stop so when I cut the throttle it kept flying at me for about 4 seconds. It backed me into a corner and I had no where to go. So I (second mistake) swatted at it like it was a small insect. BIG mistake! I almost lost a finger on my right hand. I bled like a stuck pig.  :o I was wondering if anyone else out there was willing to admit their bonehead mistakes. lol

Mateusz

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Re: Multi Rotor attack!
« Reply #1 on: January 26, 2017, 03:33:10 pm »
I usually test my new builds and fail-safe without props indoors. I always use 0% throttle or no pulse as best fail-safe option. Some people set 10% but that's horrible idea, never do that, as that value depends on aircraft weight which might change if you remove camera or surface of the props and other factors including configuration. Best is to make sure motors are cut from the power (stop) immediately when there is no signal or fail-safe triggers.

I never had problems with fail-safe with LP, though I had issues with Cleanflight so I am always checking just to be sure.

Que

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Re: Multi Rotor attack!
« Reply #2 on: January 26, 2017, 05:18:09 pm »
Thanks for the reply Mateusz. So what was your bonehead mistake when you were getting started?

Re: Multi Rotor attack!
« Reply #3 on: January 26, 2017, 05:44:13 pm »
It was raining outside but i wanted to test Altitude hold....
So i just tested it inside the house, works great for the first minute...
But then it goes straight up into the overhead light...Then there was a beautiful shattered rain...Thousands of small glitter stars falling down on me...
That was enlightening :-) , Will never do this again
Hardware: F450 Frame--Revolution Board--EMax 2213-935kv--BullTec 30A Opto--5000mAh 3S 30C LiPo--NEO M8N GPS+MAG--Fr Sky Taranis Plus + OPLink Mini
Addon: sj5000x + two axis gimbal + minimosd + eachine VT + easycap
Software: Black Rhino, LP2GO

Re: Multi Rotor attack!
« Reply #4 on: January 26, 2017, 06:02:28 pm »
I was carrying armed quad and transmitter while opening a gate in a fence.

RTB mode.  Throttle got bumped.  RTB engaged.  Bank angle compensation built into RTB boosted the throttle high.  An issue in altitude PID2 stuff kept the throttle high, making things worse.  This was a 330 quad with mild 2212kv1000 motors with flexible cheap 9 inch plastic props with rounded tips.  This makes me even more afraid of carbon props and powerful, high RPM motors.

Slightly graphic descriptions of injuries:

It was 50m in the air by the time I got my bloody (literally) hands controlling it.  It's not fun flying with badly lacerated hands, but I did get it back down safely.  Luckily my thumbs were OK, so blood didn't get into the transmitter.  It warranted getting stitches.  I will avoid a description ;) but I have medical training so I spent an hour carefully bandaging several fingers and it healed well.

CleanFlight:
While testing an RTF CF quad (so this may not be CF defaults), I saw that issue too.  Motors off, switch off the transmitter and the motors come on for a few seconds (it is a landing mode).  Safety is why the default failsafe is "motors off" in LP at least.

ernstock

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Re: Multi Rotor attack!
« Reply #5 on: January 26, 2017, 08:24:22 pm »
Yeah , I've had my small incident - land , forget to disarm , go to change battery and knock tx over , throttle goes up , fingers go ow.
Have learnt my lesson - now always disarm , and treat my quads with respect til that battery is disconnected.

Que

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Re: Multi Rotor attack!
« Reply #6 on: January 26, 2017, 09:04:21 pm »
Good stories guys! I hope we can keep this going...might help another new guy avoid some of the same mistakes. Sometimes I don't think people realize how dangerous these multi rotors are until it's experienced first hand. (no pun intended). These are some pretty wicked stories that could have ended much worse. I'm glad everyone survived with limbs in tact!

Re: Multi Rotor attack!
« Reply #7 on: January 27, 2017, 02:42:00 am »
Yep... not disarming is a bad habit that bit me in the butt,... or the thumb rather.

Que

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Re: Multi Rotor attack!
« Reply #8 on: January 27, 2017, 11:56:22 am »
OUCH!

Mateusz

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Re: Multi Rotor attack!
« Reply #9 on: January 27, 2017, 05:06:36 pm »
Thanks for the reply Mateusz. So what was your bonehead mistake when you were getting started?
I guess nothing as spectacular as limbs flying around ;) just copter inverted without props but testing with battery and smoked motor for no reason. Sorry if that story disappointed you ;)

Que

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Re: Multi Rotor attack!
« Reply #10 on: January 28, 2017, 01:42:29 pm »
lol...not at all.  :)

Re: Multi Rotor attack!
« Reply #11 on: January 28, 2017, 05:03:27 pm »
I have a few...here is one:

It was my first quad built from scratch. It was also my first real project where I had to do so much soldering, research and planning...i was so proud when it was completed and the motors spun! (without props )

It was dark out, so I couldn't take it outside to see my creation fly....i know this is an outdoor only build, but all I want is to see it lift off...Just a few inches...it'll be fine for a second...

So I go to the basement, I put on the props...arm....Little throttle...Props spin but no lift off...Don't want it to jump off the ground too quick so just a little more throttle......Little more.....Ah yes! The back is starting lifting off a tad! It's gonna fly!...

In what felt like an instant, the back of the quad lifted faster than the front and it started scooting across the floor...and *BAM!* the front props hit the floor and shattered into fragments all across the basement!

I just stood there for a few seconds like O_o

It never actually lifted off. Luckily the back props and everything else survived.

Edit:
lesson 1: don't fly something indoors that you made for outdoors.

Lesson 2: quads can't self-level on the ground, but they sure will try if the motors are spinning. I think that and inexperience caused my problem
« Last Edit: January 29, 2017, 12:30:41 pm by crof2003 »

cato

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Re: Multi Rotor attack!
« Reply #12 on: January 28, 2017, 09:24:42 pm »
Especially in the beginning or when impatient I tend to forget to disarm. So far no limps hurt but, once I tested my 250 inside, hovering it in my living room. I wanted to fix sth, so I landed it on the piano bench. The bench has a slightly bent upholstery, and instead of balancing on the top, it slowly started to slip to the ground. Just as a reflex I tried to catch the quad and in the movement hit full throttle.

The quad (carbon frame) with only 1806 motors, but very light, shot up vertically and hit the ceiling in the fraction of a second at absolutely frightening acceleration. A small hole in the ceiling reminds me of that moment every day ;)

The result was two broken props, and two broken motor axes.

Nighthawk 250, MT1806, 12A ESC OneShot125, Revo, M8n GPS, FPV
Cinetank MKII, Elite 2216, 30A Afro OneShot125, Revo Clone, M8N GPS

zukenj

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Re: Multi Rotor attack!
« Reply #13 on: February 03, 2017, 05:10:29 pm »
Hello all,

I was finishing my 450 build, and I was having an issue with the radio, and the radio wizard to recognize the 3 way switch. So I plug the FC to the USB without removing the Props and Battery. Then, I learned why there is a WARNING to remove the propels in GCS. The quad took off, extremely fast, passing in front of my face, and hitting the wall. 4 holes on the wall, 4 motors lost and 2 prop shatter. I was hit in the mouth by a prop piece. Ugly swollen and bruised mouth for 3 days.

Never again.

Lesson: Unplug Battery and take Props off, before re-program your FC. Wait for GCS to ask you to plug the battery.
FS-TH9X RC
F450 Clone
Revolution FC
EMAX 2213 935 KV
HK 30A ESC UBEC running BLHeli 14.4
10x4.5 Propellers
DJI Naza clone Ublox M8N GPS