Arducopter AC 3.1.2 Loiter test on PX4

Finally I've gotten stable Loiter, by getting GPS and Compass away from pesky annoying interference. I wasn't able to show long-duration position hold as I had planned, because my battery went flat a bit early :) The AC version I am using is quite old, so it is not representative of current AC Loiter state. I have also done minimal tuning of nav/loiter when doing the test. The frame I am using is a HobbyKing Q450 (really a Whirlwind FY450), equipped with generic 20A ESC's and NTM 28-30S 900 motors spinning unbalanced 1045SF plastic props, so the PX4 is seeing quite a lot of vibration. The GPS is a uBlox Neo-7M + HMC5883l compass from HobbyKing: http://hobbyking.com/hobbyking/store/... Camera operator is    / hamartinse