XAircraft X650 Pro Crash - Seeking Cause

[SKYCAP]

I was doing some practice flying this afternoon and my X650 Pro took a plunge from 30 feet. Any help determining the probable cause will be greatly appreciated. There was no sudden stick movements on my part and I was flying in GPS Attitude mode.

I have posted a 30 second clip of the crash on youtube at https://www.youtube.com/watch?v=Mxoczv5jWLk

When viewing my flight log, I noticed that throughout the flight, M1 power was running about 10% lower than the other 3 motors. Then in the last 2 steps of the log, M1 goes wiggy with power dropping to 11% and then bouncing up to 96%. I am hoping these readings will shed light on the cause.

My flight log is at http://log.xaircraft.com/#2014_03_22_122103.750_138.1.04.43

 

[X650Mouse]

I was doing some practice flying this afternoon and my X650 Pro took a plunge from 30 feet. Any help determining the probable cause will be greatly appreciated. There was no sudden stick movements on my part and I was flying in GPS Attitude mode.

I have posted a 30 second clip of the crash on youtube at https://www.youtube.com/watch?v=Mxoczv5jWLk

When viewing my flight log, I noticed that throughout the flight, M1 power was running about 10% lower than the other 3 motors. Then in the last 2 steps of the log, M1 goes wiggy with power dropping to 11% and then bouncing up to 96%. I am hoping these readings will shed light on the cause.

My flight log is at http://log.xaircraft.com/#2014_03_22_122103.750_138.1.04.43

First observation is your battery dropped to 13.8 volts momentarily that triggered a drop in height (crash) whilst the battery recovered the vehicle was on the ground at that time, fell from nearly 10 meters.

The other observation is that you motors are not aligned (level) whilst the vibration is good indicating the props are okay M1 is not pulling with the other 3 take a look at the log as you fly M1 is very low on power compared to the others

Good luck

David

 

[SKYCAP]

Hi David - thank you for your time looking at this. Could the sudden drop in voltage be due to the surge in power to M3 at 99% at that point in the log? If so, what can cause that to happen other than stick movement? I was in a smooth pan as I flew by myself applying a bit of right rudder and a bit of left aileron. I was just transitioning elevators from positive to negative (up stick going to down stick). All very light on the stick.

 

[X650Mouse]

Hi David - thank you for your time looking at this. Could the sudden drop in voltage be due to the surge in power to M3 at 99% at that point in the log? If so, what can cause that to happen other than stick movement? I was in a smooth pan as I flew by myself applying a bit of right rudder and a bit of left aileron. I was just transitioning elevators from positive to negative (up stick going to down stick). All very light on the stick.

A battery dying is just that, a collapsed cell or some other issue, best to user a charger to discharge the battery and then balance charge it back up, but use it with caution, these events give no warning other than a broken vehicle, once the battery dropped to that level SuperX would have entered a low power state and headed for a landing, These type events are never gentle especially at height, that's why we have battery alarms fitted.

David

 

[SKYCAP]

I checked the battery and all cells are balanced. I haven't charged it and it is at 57% charged. Can a cell collapse and then regain its power?

There was no low battery warning prior to the moment of the crash. Right when it dropped, the lower battery warning did flash for a second on my OSD. I know this can happen when sudden power is applied.

In the log, you can see that M1 drops to 11% and M3 goes to 99%.

I am trying to understand why all motors wouldn't lose power under a failing battery scenario.

 

[Aerovideo]

Watching your video and looking at the logs it sounds like all the motors dropped in the video and in the log at the end of the flight it looks like the throttle dropped to zero briefly. I have had quads drop out of the sky due to dead batteries but the log reports a huge drop in throttle and I'm guessing you didn't do that so it almost seems like maybe you had a brief receiver lock out and didn't have any failsafe set so the default failsafe for most Rx is zero throttle. But you're so close to the model it's strange you would have a lockout. Is your video transmitter really close to your Rx? What frequency of Rx and Video are you using?

This may not be the case, just trying to help with some issues I've experienced before.