Listen to the warnings, remove props before any calibration - warning, images.

[nilsen]

So I was messing about with my large hex the other day with the 13inch CF blades.
Just finished flashing SimonK onto the ESCs and was in the process of calibrating them, manually using the throttle channel on the reciever directly to the ESC signal cable (the APM calibration isn't so good, or maybe I just dont trust it) either way, when dealing with 4s batteries and huge props, always, always remove the props.

I had bought some steaks for my wife any I to enjoy and if someone doesn't know, meat in Switzerland is RIDICULOUSLY expensive but I thought we would have a treat.

I just finished them, my wife had jumped into the bath and was finishing off and we're about to eat when I calibrated the ESC while waiting for her to come and eat.

I throttled up the radio, connected the battery and successfully calibrated the first ESC.

I then unplugged the signal cable, and moved the it to the next esc without throttling down.

It spun up instantly to full throttle and started lifting off.

I grabbed at the frame but the huge prop nicked my arm...

***Warning, images ahead****


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We spent the next hour at the hospital having it stitched up and it's all ok now.



This was completely avoidable and stupid and I'm to blame so be careful and remember that it can happen so fast and the warnings are written for a reason

Cheers!

 

[cranialrectosis]

Remove props before testing failsafe too.

Sorry you learned this way, nilsen. Thank you for posting about it and for the photo warnings.

Nothing gets the wife to finish her hair like a 'hun we need to go to the hospital!'.

I hope your steak dinner was ok in the microwave.

 

[kah00na]

Ouch! My friend, who was new to quads, wanted to do some on-the-field calibrating on his F450 with 8045 props. I said before you do that I'm going to hold it down. Sure enough, something went wrong and the propellers spun like crazy for a few moments, but I was able to hold it to ground. I figured something like that would happen so I made sure I had a good grip and my arms were out of the way. No damage. I didn't even panic because I was kind of half expecting it. My friend freaked out for a few moments and started apologizing but I told him it was fine. He takes his props off now.

 

[BurningArmada]

Ouch! Glad to see that you only got "minor" injuries from those massive props. It could have been much worse. Thankfully for me, I learned my lesson about props early on when this same thing happened to me. Luckily for me, the quad did a flip AWAY from my face and landed bottom up on the table. Testing/calibrating = props always off!

 

[Cyberdactyl]

I was SO happy my experience was with slo-fly flexible props. They hurt, but don't cut too deep. I'm positive if they had been carbon fiber, it would have looked like I'd had a fight with Freddy Krueger.

TAKE OFF PROPS WHEN TESTING YOUR MULTI-ROTOR

Just thought I'd reiterate that, but mine was not from testing, but carrying it armed with the ancient V2.1 (atmega168PA). I was slipping though a tight gap between the garage door and my pickup truck and the tx strap snagged the throttle.

 

[nextmoneypit]

YIKES!! Thanks for posting guys...I'm sure a lot of people will heed your advice.


While on the subject: what situations cause quads to full throttle when losing TX? I've only heard/seen it happening on my friends RC truck...we were in the pits between races fixing our trucks..he just got a new TX and when he switched it off, BLAM-O the truck went balls deep on the throttle and drove down a few people's pit tables haha...left my buddy with one red face lol.

I haven't had that experience with the KK (but I've never tried to switch off TX while the board is armed...only disarmed). Glad everyone made it out alive!!

 

[Craftydan]

Easiest way it can bite you on a multirotor is setting a failsafe on a quad (to anything other than "fall from the sky"), then turning off your TX while it's armed. Props may not got WOT, but they will come to life

Another way is reprogramming or recalibrating the ESCs through the board -- wierd signals go to the ESCs in those cases and if they dont' quite understand them, they can go LIVE! In genral, I don't power a board through the ESCs when reprogramming -- the board gets it's power form the reprogrammer or UBEC, but the ESCs are left unpowered to prevent this.

*Some* boards, like the Naze, have menu modes that will power the motors for testing (connection tests and vibe measurment), but they have warnigns . . . Heed them. If the instructions say "remove the props", just do it (he says with the authority of someone who doesn't always follow the instructions, even though he knows better).

 

[nilsen]

Well I have certainly learned my lesson, I can imagine failsafe must be even more brutal with all 4 (or 6) rotors would spin up and try and take it somewhere such as into your face

While on the subject: what situations cause quads to full throttle when losing TX?

There is a setting on your radio called "Failsafe" and it is different to the FC failsafe which is much more controllable and customizable.
The throttle failsafe on the radio can perform an action on one or more of the channels which the radio is transmitting so for example:
"On loss of transmission set throttle to 50%"
If you then turn off the transmitter or lose range the throttle channel will be set to 50%.

What this does is in case of a "dumb" quad you could say "On loss of transmission set throttle to 0%" and your flying thingie will fall out of the sky or your RC car will harmlessly sit at your feet

 

[RAM]

This is why real pilots use a checklist. Too easy to get complacent when it comes to safety.

 

[cranialrectosis]

I treat my copters like firearms. When the props are on, the copter is 'loaded'.

 

[Christopher14]

I don't fly multirotors, but I like to fly fast planes. When you have a 4.7inch prop going almost 50,000rpm, you take it seriously. I have only gotten cut once, and that was a FT Flyer with a slowfly prop at less then 1/4 throttle. I was lucky.