Hi everyone, thanks in advance for reading my note here. I did do my best to read all the docs but could not find exactly what I was looking for - am hoping you much more experienced drone fliers could help a noob here...

I bought my excellent hexacopter from USR just over a week ago and have gotten the various additional parts (radio, batteries) together to fly it.  Today I finished my ESC calibration and, being a coder, habitually updated to the most recent firmware (eg 2.8.1 to 2.9.1...).  Hm.  I then realized this involves some uh, recalibration, and did my best on that.  Carefully calibrated the accelerometer as in the ArduCopter 2.9.1 instructions on this forum.  And redid it a couple times to be sure... but I don't think that's it.  Have not yet added vibration dampening, since I just got the USR drone and need to get more parts to make room for foam (could the lack of foam be leading to my symptoms below..?)  I checked my PID values in the ArduCopter Config - they were as shown in the 2.9.1 instructions.

So when I carefully throttle up - as soon as the hexacopter lifts off it goes into a mad spin - either to the left or to the right.  The yaw control does seem to have some effect - I can make it spin right or left.  And it seems like it wants to start spinning faster and faster before I throttle down.

I was thinking to try to tweak the stabilize yaw value - but not sure what value to try and also, seems like the problem could be larger than this..?

Or am I missing something on resetting the gyros before flight ..? or ..?

I'd greatly appreciate any thoughts you might have on this... thanks again for your help and I hope to someday repay the favor.

Quinn