Discussions

I recently built a Tarot 680 Pro hexacopter, but had to rebuild it after the PCB failed on me.  For those not familiar with the Tarot 680 Pro frame, it's a mostly a carbon fiber frame.  One plate on the body is a PCB however which is used to distribute power, and this is how I had everything connected originally.

Tarot 680 Pro Example: http://www.robotshop.com/en/tarot-680-pro-folding-hexacopter-frame.html?gclid=CMSZj4O9wMMCFYqIfgodbawAUQ

Build Specs:

Pixhawk Flight Controller

SunnySky 4108S 380Kv Motors (x6)

Tarot 680Pro Carbon Frame

DX6i Transmitter

6S 6000mAh Turnigy Battery

Unfortunately, I don't think the PCB was made to handle the voltage of a 6S lipo and it ultimately burned-out on me (on the bench thankfully).  Prior to the burn-out, I had 2 or 3 successful flights after performing an all at once ESC calibration, radio calibration, etc.

Suspecting the PCB wasn't built to handle 22.2 volts and the near 90 amps these motors could draw collectively at 100% throttle, I decided to avoid using the PCB on the rebuild.  I ended up ordering another carbon fiber body plate and did a completely different power distribution when it came time to put everything back together.

Problem.  Upon getting everything back together, I noticed the copter would not take off properly as if I had never gone through an ESC calibration before.  Thinking another ESC calibration shouldn't be necessary as I was using the same motors, ESC's transmitter, etc, I attempted a first flight using the new power distribution design.  On completely level ground, I can see the copter trying to lift off unevenly.

Question 1:
Should ESC calibration be necessary again, or do I perhaps have an issue with my power distribution re-design?  (note: all the motors do spool up)

Question 2:
I understand the importance of ESC calibration so that they know the min/max settings of the transmitter throttle stick, but why would an uncalibrated system attempt to take off and fly "unevenly" when the Pixhawk has a built-in gyro and desires to stabilize itself?  Shouldn't the Pixhawk be able to compensate for uncalibrated ESC's?

Thanks in advance for your help if you can answer either or both questions.
Regards,
Erik