[proctoidpaul]

I've got about 8 hours of flight time on my Quanum 270 from Hobby King.

http://www.hobbyking.com/hobbyking/store/__85286__Quanum_Outlaw_270_Carbon_Fiber_Quadcopter_Racer_Set_ARF_.html

It has always flow nice and stable... unitl...

A few days ago I started hearing a bit of a weird sound out of the motors.  I thought perhaps a bearing was going bad.  Then a couple minutes into the flight, one motor cut out.

I [perhaps incorrectly?] diagnosed the problem as a bad ESC and ordered/installed a replacement.

The replacement didn't physically look exactly the same (one chip looked different).

When re-running the vehicle setup wizard, the factor for starting motor spin was different on the new ESC (1062) vs the other 3 (all at 1116).

Other than that, setup went fine.

In flight now I have a slight "wobble".  (That was also present after installing new ESC w/o re-running the setup wizard.) Quad just kinda shakes on all axis just a bit, but is controllable.  But wait... there's more.

It is also occasionally doing a full cut on all four motors simultaneously, sometimes for less than a second (ie: just enough to fall a foot or so).  I can post a video if helpful.

I've double checked on two [short] flights that this isn't a RX/TX issue (Checked with flight log tool on Spectrum).

Do you think I'm looked at a bad CC3D board?  Or is possibly something else going on? 

While going through everything I dissembled motors, cleaned them, and oiled the bearings (with high-speed oil from Boca Bearings).  After running for a couple minutes the motors actually feel just a bit tight to spin and one of them spools down more quickly than the others.

Paul

[f5soh]

You should recalibrate your ESCs and get the same starting value like others.

[proctoidpaul]

I ran through the calibration multiple times, got exactly the same results each time.  So that part 'is what it is'.  Although the replacement ESC was the same brand and model, it did have a slightly diffent chip configuration.  I don't know if that is the source of some of the issues of not. 

But even if so, does that explain the full power cut (all four motors simultneously)?

Paul

[f5soh]

Looks like there is two issues.

[proctoidpaul]

There were in fact to [rather unsuspecting] casues.

1) I tracked down a poor connection in the main wiring harness from the CC3D board.  This was dropping the signal to one motor, which was causing the unexplained "drops"

2) The real culprit was an [extremely] out of balance prop.  I'd heard it said not to bother balancing these small props.  That certainly is bad guidance.  The "tip to tip" balancing was fine.  But one of the 4 props was VERY out of balance on the "hub".  If you're not familiar with how to balance the hub, google it.  There are some really easy to follow instructions out there on YouTube.

I've had to remove at least 1/3 of the hub on one side of this prop.  And it still isn't fully balanced.  But per a test flight I just did, the instability is just about gone.  I frankly don't know how such a small prop could be so grossly out of balance, but that's the underlying issue!  The vibration from this was then aggravating the poor connection.

Thanks for the replies!

Paul