Quadcopter falling out of the sky

[meehan]

About a week ago I was flying my quadcopter FPV 5 meters off the ground maybe 50 meters away and it just fell out of the sky. The battery broke loose in the crash so I could not tell if I lost signal or what.

Today I was flying line-of-sight about the same distance and it happened again, all motors just shut off. I was on a fresh battery and when I got to the quad the receiver did not indicate loss of lock and the KK board was still armed. I powered on and off put in a fresh batter I took off again flew for a a minute just hovering 2-3 meters away and all motors just shut off again, no loss of link on reciever and KK board still armed.

I searched and found some references to buggy kk2.1.5 software from HK and I plan to reflash the board but does anyone have an idea of what is actually happening? I have had this board through close to 100 flights on stock firmware. My guess is the board gets a wacky reading from one of the sensors and just shuts down. Does anyone know if there is a way to get out some error codes?

Tim

 

[cranialrectosis]

Lots of possibilities here but I would start with a range test.

Do you have signal 50-75 meters away from the transmitter?

How much voltage is in your lipo when the shutdown happens?

 

[meehan]

Lots of possibilities here but I would start with a range test.

Do you have signal 50-75 meters away from the transmitter?

How much voltage is in your lipo when the shutdown happens?

Good questions and I should have been more specific. Yes over 12 volts on the 3 cell lipo. Has happened on different known good batteries. I performed a range check with the DX6i at 50 paces and was able to arm/ disarm. I am using an orange rx that always gives me the flashing light if it looses link and the light was solid on the last two falls, (first fall battery came out in the crash so light was off .

I am also going to start looking for intermittent shorts but I would have thought if the voltage dropped enough to cause the KK board to stop all the motors it would have also reset and not remained armed.

 

[cranialrectosis]

What motors/rotors are you using?

How are you preventing vibrations from the motors/rotors from hitting your accelerometers?

 

[joshuabardwell]

What motors/rotors are you using? How are you preventing vibrations from the motors/rotors from hitting your accelerometers?

I appreciate that it's always a good idea to reduce vibration, but I have to wonder: is there really some way that excessive vibration could cause the FC to kill the motors?

If OP suspects a bug in the HK firmware (and from what I hear, there are lots), I suggest flashing with Steveis.

 

[Twitchity]

What about the ESCs? I've had a few planes fall from the sky due to the ESC overheating and shutting off. The ESC worked great when I first purchased it, but after many flights it started to give me problems. This probably isn't the likely culprit, but figured I'd mention it in case you have your ESCs sandwiched somewhere where they don't get good air flow and could possibly overheat.

 

[rcflyer729]

the orange rx I had one and it was junk i would NEVER!!!!!!!! fly with an orange rx they are awe full and loos signal all the time even if this was not your problem i would get rid of that orange rx

 

[meehan]

I am running turnigy park300 1080kV motors. Props are ballanced and KK2 board is mounted in the foam case it came in, I wont rule out vibrations but I think it is unlikely.

I had ruled out the ESC becuase all the motors stop at once but maybe the KK board does something weird if a single ESC board suddenly fails. I will add ESC back to my list of things to go through.

I am going to do a bunch of testing tonight to try to identify the problem. I'll take some video of the process. I will update when I finally figure it out.

Tim

 

[ExperimentalRC]

Check for any loose connectors, and that everything is soldered and firmly in place. Something could be coming apart when it's flying, and when ur takes a crash it could be coming back together.

 

[meehan]

I have put about 25 flights on this since the last problem and have had no issues. I am beginning to think it is water related, I had been landing in 1-2 feet of really wet grass. It has been dry the last week so no more water. I ordered a can of corrosionX and sprayed everthing down last night. I will post again if the problem comes back but at the moment I am writing it up to water in the ESC, FC or rx.

 

[Tritium]

I have a KK2.X on the bench with a similar issue. Looks like it was poorly soldered at the factory. Inspection under magnification showed many loose solder balls rolling around the board which I suspect were causing intermittent shorting of the board's chips.

Thurmond