Quad fall out of sky but I can not figure out why $^#%&@&&*

[jimboo]

I need big help here. My quad fall of of sky but I totally cannot figure out why :-(
While I was flying, all a sudden I try to gain altitute but it just won't go up even I push up the stick to maximum.
I then realise something must have gone wrong and trying to fly it back closer to my position.
All a sudden it just spin out of control and fall. Totally no idea why it happened. Lucky it was only few meter high, I think the major damage caused while it spin out of control.

First thing I do is measure the battery but it still have 79%

Similar situation has happene to me before but I landed my quad right away so no damage done previously. I was bit lazy this time and suffered this fail

One time it happened I switch it to manual mode and it flys really well and fly up really fast, switch back to GSP it just fall slowly. Maybe it's not battery problem??!!

I really appreciate anyone's opinion here and help me on how to prevent this in the future as I am building a new X8 with WK and I want to turn the old one into Y6. Have it fall again will cost me arm and leg They are really expensive.

Foxtech quad frame
NAZA M2 with GPS
Turnigy Nano tech 4500mah 25c
T-motor 900kv
DJI 30A ESC
Futaba 14SG &R7008SB
No PSB, I use wire and solder them together

 

[sixshooterstang]

Any loose props? Turn off that stupid second stage off voltage detection on the naza its inaccurate crap (and causes alot of crashes)

 

[Carapau]

The demand to gain height quickly will have caused a voltage drop as the battery tries to meet the demand. This has either caused the low voltage protection to kick in or worse, because you have a soldered PDB, the high current has caused a problem there. If you are going to solder your wires for power distro then your solder needs to be top notch and that is not always easy to tell.

 

[PeteDee]

Turn off your LVC, fly to time.

Pete

 

[sixshooterstang]

I never use any low voltage cutoff a only alarms

 

[jimboo]

Thanks guys, now lesson learned. I thought that 2nd voltage warning is would be life saver especially for newbi like me.
I was relying on that 2nd voltage warning very heavily as most newbi would do. Now I will go back to old school timer and telementry.

BTW I checked the props, all broken but centre still attached to the adoptor and tight. Guess it's not props issue.
Thanks for the tip on the wire soldering, I will get my electrician friend to help me on my new build just in case.

I wounder why will caused the crazy spin? If 2nd volage cutoff kick in, it would just land and not cause the MR to spin, isn't it?

 

[Carapau]

I wounder why will caused the crazy spin? If 2nd volage cutoff kick in, it would just land and not cause the MR to spin, isn't it?

Hence why I was wondering if there is an issue with the PDB

 

[jimboo]

It might be one of the cause by my wired PDB.

1, wires too long between ESCs. It basically go around the whole center piece. Maybe also generate too much noise to receiver and FC?
2, I wasn't confident with my solder job linking 2 wires together. So I used bullet plug as bridge joining 2 wires together.

Lucky I started off with a small quad to experiment instead of go straight getting a large Octocopter.