I would recommend a long straight 300m passing overhead, and fly there and back several times (10?12?), for tuning.
Then enlarge to 400m, if you are sure it is switching waypoints.
make sure you have PLENTY of altitude, like 100m AGL.
you can expect 50-70m overshoot (turn radius) when properly tuned.
so only 50% on the shorter legs and 75% on the longer legs will be straight, but again, when tuned.
Replies
in ML7_18 you can see what you can expect with a plane not fine tuned for this pattern.
In ML7_17 another pattern that better represent the actual tune of the plane.
Ric
ML7_18.kmz
ML7_17ca.kmz
Then enlarge to 400m, if you are sure it is switching waypoints.
make sure you have PLENTY of altitude, like 100m AGL.
so only 50% on the shorter legs and 75% on the longer legs will be straight, but again, when tuned.