I am plagued by poor loiter on the SK450 and have made further changes to improve things:
- Fixed the slop or wobble in the GPS mast. It turns out that the cheap mounts rely on being able to screw down the knurled flange until the mast mount inside is snug. However, a lot of them cannot be tightened. I added a plastic washer from an old prop to the mast as shown and the wobble stopped.
- The APM mount was maybe moving in flight, so I remounted it with the special vibration reducing foam rubber and I secured the USB cable better so it could not move the APM.
- Added a little foam rubber inside the micro APM case to ensure the barometers were not getting fooled by the prop wash.
- Wait 5 minutes after power on to get the GPS and all sensors stable before trying a flight.
- Added some practice golf balls to the landing gear so they do not catch in the grass when taking off or landing.
- I very carefully recalibrated the accelerometers, making sure that the quad was absolutely level during the first stage of calibration. This made a HUGE difference versus my previous "it looks level" calibrations - the test flight was much beter with much less yaw and pitch on takeoff and during flight.
- Made a stand out of a medium size plastic storage container as shown: