Just how important vibration isolation is with an APM become clear to CanberraUAV this week. We were testing flying Jacks SkyRaider (a low wing sports plane with a 0.5ci engine) on Sunday, and found that we got severe gyro drift. The first minute or so of flight was OK, but the plane quickly developed severe roll and pitch drift when it stabilize mode. We were recording the flight using a mavlink log which showed that the roll went from -2.97 radians to 3.09 radians, when in fact we were flying fairly level!
We tried swapping out various APM components with known good bits from my SkyWalker, with no luck. Chris Gough then suggested that the problem may be vibration, given that the SkyRaider has a glow engine, and the only vibration isolation was some double sided tape between the APM and the fuselage. On Wednesday we tried again with a thick layer of foam beneath the APM (see the above picture), and it worked fantastically! We would quite surprised quite how much vibration isolation mattered.
I've mounted the APM for my Senior Telemaster with an even thicker layer of foam: