In my third flight test of the Bix3 QuadPlane, I tested Hybrid RTL. In Hybrid RTL, the QuadPlane starts its return to home as a fixed wing aircraft until it is close to the return point at which time it switches to a VTOL RTL. Before testing Hybrid RTL, the video shows several flawless transitions from QStabilize mode to FBWA and back.
My settings for Hybrid RTL were as follows:
- Q_RTL_MODE = 1 (Hybrid)
- ALT_HOLD_RTL = -1 (keep same altitude)
- Q_RTL_ALT = 20 (meters)
- RTL_RADIUS = 100 (meters)
- WP_LOITER_RAD = 200 (meters)
Although the Hybrid RTL worked and brought my QuadPlane safely back to a landing, I had two issues.
Issue #1 was the "porpoising effect" that the plane had when initially returning to home. It reminded me of the Olympic swimmers in Rio doing a breast stroke.
Issue #2 (as denoted in the video) showed up when the QuadPlane was descending as a copter. About half way down to the ground, it lost the Loiter lock and started to drift like in QStabilize mode. I decided to compensate with my right stick forward to keep it from drifting while it landed by itself.