|Micro APM mounted on standoffs on plywood base|
After many days of debugging Pixhawk problems with ESC calibration, channel mapping, poor stability.. I put it aside and went back to an APM 2.7 unit for the SK450 dead cat. The pixhawk seems like a nice unit, but the factory support was mediocre, the warranty is 3 months, and it seems pretty finnicky about ESCs, powering, and such. Online support from forums is usually helpful but not always and not in this case.
Removing the Pixhawk was reasonably easy but the APM was a pain as it is a micro unit and is not nicely packaged. I mounted it on standoffs as shown and replaced the GPS with a known good unit as well, let's see what happens.