Discussions

I'm building a 450 class quad using APM 2.8 and an 8 channel PPM Spektrum compatible receiver. I've completed all the first flight calibration and pre-flight checks, including all-at-once throttle calibration. Now for the first test flight - every time I attempt to take off the quad wants to tip over to the right (starboard) side. I'm using stock Gforce Multirotor 30amp ESC's with SimonK firmware. No power distribution board - all ESC's are wired into a custom harness and JR connectors run straight to APM with center 5v wires disconnected.  

With the props off and the quad on the bench, and reviewing stats in the bottom left window of Mission Planner, RC OUT 1 and 4 show around 1100 but RC OUT 2 and 3 are around 1500 at motor start. Then as I advance the throttle, the pairs advance maintaining the same gap of roughly 400 between them. 

I thought this was an ESC calibration issue, so I swapped out the PPM receiver for a standard PWM receiver. Connected all four ESC's at once using Y cables and repeated throttle calibration independent of the APM. Then I reconnected the ESC's to APM and repeated the bench throttle test. The results were exactly the same, with about a 400 gap between sets. 

This is leading me to believe that APM is telling the port side motors to run faster than the starboard pair. I don't know why it would do this unless some other aspect of my calibration process went awry. Perhaps APM thinks it's listing to port and is trying to correct? But the roll and pitch numbers are pretty much zero out to four or five places. 

I've spent hours messing with this over the last few days, repeating calibration steps and reviewing forum discussions, and am finally at the point where I need to ask for help. 

Thank you,

Neil