XAircraft Sudden momentary drop in voltage

[mediaguru]

I have a concern with my T960 now.

Please check this log at 145 seconds. I was coming in for a landing about 25 meters up and the bird dropped and regained attitude a second or so later. What do you think is the issue? Obviously time to check all power leads and wiring as there was a sudden voltage drop.

http://log.xaircraft.com/report.htm#2014_09_23_190202.250_75.1.02.47

 

[kloner]

that was from all that pitch and throttle making the voltage sag.... you had to be drawing some serious amps when it did that, question is what made it do that..... 95% + throttle. all i saw in the radio command was throttle, i'd look at bullets, my guess would be a rosin insulator on the bullet itself, might use a solvent and scotch bright on all them... since was a negative pitch i'd look at the rear motors.... assuming that's the side that dropped,,,, could also be a motor bearing leaving but usually those don't recover very well and show a lot of yaw un authority prior

 

[mediaguru]

that was from all that pitch and throttle making the voltage sag.... you had to be drawing some serious amps when it did that, question is what made it do that..... 95% + throttle. all i saw in the radio command was throttle, i'd look at bullets, my guess would be a rosin insulator on the bullet itself, might use a solvent and scotch bright on all them... since was a negative pitch i'd look at the rear motors.... assuming that's the side that dropped,,,, could also be a motor bearing leaving but usually those don't recover very well and show a lot of yaw un authority prior

Interesting point. I was coming down when the bird simply started to drop, almost free fall. A second or so later it seemed to realize it was dropping and it leveled itself by hitting the throttle. I didn't do anything. So the drop in voltage is the RESULT, not the cause.

 

[mediaguru]

Here's a video of the drop, at 3 seconds. Since the FC and gimbal still had power do you think perhaps I just went too low on the throttle? Pilot error? I could swear I was not touching the throttle at the time.

 

[kloner]

seeing the video and the graph under rc control, you dropped the throttle to 5%.... so yes, that's a pretty high probability.... close one.

 

[mediaguru]

seeing the video and the graph under rc control, you dropped the throttle to 5%.... so yes, that's a pretty high probability.... close one.

Seems like a solid diagnosis. Thanks. I must admit I haven't flown this bird for 2-3 weeks (waiting for FPV parts and had it torn apart). A little rusty I suppose.

 

[mediaguru]

So how much throttle is too little?

 

[kloner]

I'm rarely less than 30%.... if i gotta drop faster i fly forward at 30%

 

[mediaguru]

I'm rarely less than 30%.... if i gotta drop faster i fly forward at 30%

Maybe I should setup an audio warning on my taranis if the throttle hits 30% or less.