I've had trouble with my Iris+ which I believe might be related to overheating. When I first got it, I only flew it near sunset, when the ambient temperature was in the low 90s, but then when I started flying earlier in the day, with temperatures around 100-105F, I began to have problems. The cabin temperature got as high as 131F (55C), and finally IMU1 flatlined on my Pixhawk. I think the cabin temperature at the point of failure was around 53C.
So I thought, maybe put some spacers to lift up the top half of the body to let the hotter air out. But would that affect barometer readings? Would I get extra pressure at speed, or with wind gusts, from air being forced through the interior of the body? And if that happened, would it cause trouble with staying aloft?
It shouldn't matter, the pixhawk is still inside a case - take a look at a 3DR X8+, they have no external casing, the Pixhawk casing is just out there in the open.
Can you read out the temperature from your log?
Somewhere in the the barometer values there is a parameter baro temp. I would be interested in what that says in case of your flights.
I noticed this neat trick awhile ago. Hook your Iris or whatever, to mission planner. While connected, quickly raise or lower the quad, and you'll see the blue bar on the right side of the HUD, go up and down. Then blow across the quad, and see what happens. On one of mine, you can definitely see the effect of the wind, against the barometer. A piece of foam across the top of the FC will help.
Yeah, the barometer temperature on flights where I've had trouble controlling the Iris+ has been 53C to 55C throughout most of the flight. When I first got it and had good flights, it would spend most of the flight in the mid-40s. That was when I was flying an hour or two before sunset.
Paint it white?