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Quad flips right-and-back sometimes on takeoff
#1
I've had the same motors and ESCs on my quad for months now and it has slowly developed a problem I'm not sure how to fix.

Sometimes, when I arm (air mode enabled, motor stop OFF) it will flip backwards and to the right.  If I don't disarm it immediately it keeps going that way dangerously fast.

This used to be a "sometimes, rarely" and last week has become a "sometimes, most of the time".  

I did figure out a little trick that if I arm, disarm, arm, disarm, arm quickly...it's fine.  It's almost like the back right motor doesn't spin up as fast as the others but the constant arm-disarm gets it up to speed.

I tried swapping out the motor with a brand new one, same issue.

I don't have an extra ESC to test that, but I see no physical damage to the ESC.

Anyone got any suggestions?
#2
Check (and even resolder) connections from PDB to ESC and ESC to motor, and then recheck them. Tiny cracks can start to form in solder joints - especially after repeated temperature changes, and forces from crashes/hard landings/etc.

Have you been able to determine any pattern to the issue? Ambient temperature, first run of the day, last run of the day? Battery voltage? Always on the same battery pack? etc? etc?... Swap ESC control leads and motor mix, see if the problem follows the control, or the ESC?

Perhaps some more details on your model may help also. Frame, FC, ESC, motors, etc.
~illushinz (CenFloFPV)

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#3
I resoldered the connections on that motor and esc (including to the PDB) this weekend. Worked fine for the first flight. Came back a few hours later and right back to the same problem. Again, if I flick the arm on-off-on-off-on really quick it works fine, but if I just arm and leave it, violent flips happen almost every time.

At this point I'm almost tempted to just rebuild the whole thing from scratch, but I'm not positive that will solve the issue and it might create new ones.
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#4
Whats escs are that and what are your min throttle settings on all?
Find me on Youtube and Instagram. I currently fly: NOX5, NOX5RAirblade Assault 130 and drive a scrap RC car
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#5
In Addition to Konrad's comment, also check

- what's your min_command / min_throttle
- what's your throttle range? (check in RC tab in GUI), also make sure throttle trim in right in the centre (the knob next to throttle stick)
- make sure your ESC PPM min/max make sure they are matched
Don't be a LOS'er, be a FPV'er :) -- My Fleet
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#6
I just had another thought - if damping is enabled on all the motors EXCEPT the front left, would that contribute to the condition you described in the OP? flipping back and right? I was just wondering that if the front left motor continued to spin (hence continue to create lift) while the other motors are braking, that could surely cause that symptom.
~illushinz (CenFloFPV)

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#7
The problem with checking all those things, is that nothing has changed about my settings in months (excluding PIDs). This is just a behavior that slowly developed and got worse. It seems better now that I've resoldered all the connections to that motor, but still happens, just slightly less often it seems.

I'm guessing it has to be hardware related based on it slowly developing and getting worse. I've already ordered another PDB, I'm just going to try to rebuild the darn thing.
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#8
I was asking for esc type, because maybe you have your min throttle on esc set just barely enough to spin the motor. Just my theory but maybe fets or what not degraded over time and it needs a slight bump up in fc settings, recalibration etc. Smile You can swap the esc to test that. Front left is the easiestchoice since it should have the same direction settings.
Find me on Youtube and Instagram. I currently fly: NOX5, NOX5RAirblade Assault 130 and drive a scrap RC car
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#9
(21-Nov-2016, 06:29 PM)KonradS Wrote: I was asking for esc type, because maybe you have your min throttle on esc set just barely enough to spin the motor. Just my theory but maybe fets or what not degraded over time and it needs a slight bump up in fc settings, recalibration etc. Smile You can swap the esc to test that. Front left is the easiestchoice since it should have the same direction settings.

Konrad makes an excellent suggestion, but a rebuild is always fun too!  Good luck and keep us updated!
~illushinz (CenFloFPV)

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#10
Konrad that is an excellent suggestion! I didn't think about that.

I might try to just up the min throttle a tiny bit see if that helps. I try to avoid doing soldering repairs because every time I do I end up breaking something else! If upping min throttle doesn't work I'll definitely try your suggestion.
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#11
what FC and software you are use?

the last time i see something was the solution to reflash the FC firmware and the Blheli!
and as konrad say keep an eye on your min throttel settings
Fly deep, fast and crash - repair and then repeat! Welcome to the Game of Drones ;)
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#12
I'm using a Flip32 (the F1 version) and some DYS 20A escs. I think they are BlHeli but I'm not sure since they're the only 4 I've ever owned, I took the wrapping off on day 1 and have never updated their firmware. Big Grin
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#13
(22-Nov-2016, 07:28 PM)jamesw Wrote: I'm using a Flip32 (the F1 version) and some DYS 20A escs. I think they are BlHeli but I'm not sure since they're the only 4 I've ever owned, I took the wrapping off on day 1 and have never updated their firmware. Big Grin
The only ones youve owned? Brother fly that thing! Or maybe I should take it easy? I've bought everything on my quad at least twice, some things three times
~illushinz (CenFloFPV)

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#14
Yeah, I have broken motors, but I have yet to buy more than the original 4 ESCs I got at the start.
I guess I tend to crash and end my flying time before I can actually push the limit enough to break an ESC. Tongue
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#15
(22-Nov-2016, 09:55 PM)jamesw Wrote: Yeah, I have broken motors, but I have yet to buy more than the original 4 ESCs I got at the start.
I guess I tend to crash and end my flying time before I can actually push the limit enough to break an ESC. Tongue

I killed 3 ESCs with prop strikes before I figured out how best to protect them.
~illushinz (CenFloFPV)

FPV noob.  
Arris 250FPV, Naze32 Rev6 Acro
ZMR250, Naze32 Rev5 Acro

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