We did the first test flights of the Unique Models CL84 TiltWing VTOL with ArduPilot today. Support for tilt-wing aircraft is in the 3.7.1 stable release, with enhancements to support the tilt mechanism of the CL84 added for the upcoming 3.8.0 release.
This CL84 model operates as a tricopter in VTOL flight, and as a normal aileron/elevator plane in forward flight. The unusual thing from the point of view of ArduPilot is that the tilt mechanism uses a retract style servo, which means it can be commanded to be fully up or fully down, but you can’t ask it to hold any angle in between. That makes for some interesting challenges in the VTOL transition code.
For the 3.8.0 release there is a new parameter Q_TILT_TYPE that controls whether the tilt mechanism for tiltrotors and tiltwings is a continuous servo or a binary (retract style) servo. In either case the Q_TILT_RATE parameter sets the rate at which the servo changes angle (in degrees/second).
This aircraft has been previously tested in hover by Greg Covey (see http://discuss.ardupilot.org/t/tiltrotor-support-for-plane/8805) but has not previously been tested with automatic transitions.
Many thanks to Grant, Peter, James and Jack from CanberraUAV for their assistance with testing the CL84 today and the videos and photos!