Fixed Wing
The standard firmware (avianautomata_305ap_default) includes PX4's fixed-wing and VTOL controllers, so the 305ap can fly planes, flying wings and VTOLs.
Fixed-wing and VTOL use the standard PX4 controllers and are supported by the firmware, but avian automata has not flight-tested the 305ap in these configurations yet. Bench-test thoroughly and take extra care on first flights.
Outputs: Servos and Motors
Control surfaces use servos at 50 Hz PWM, and the motor uses an ESC. The eight outputs are in four timer groups, and all outputs in a group share one protocol and rate. Plan the wiring so servos and ESCs sit in different groups:
| Group | Outputs | Example use | PWM_MAIN_TIMn |
|---|---|---|---|
| TIM1 | MAIN 1–2 | Throttle (ESC) | DShot300 or PWM 400 Hz |
| TIM2 | MAIN 3–4 | Ailerons | PWM 50 Hz |
| TIM3 | MAIN 5–6 | Elevator, rudder | PWM 50 Hz |
| TIM4 | MAIN 7–8 | Flaps, other servos | PWM 50 Hz |
Assign the functions in Vehicle Setup → Actuators after selecting the airframe. Check each surface moves the right way with the actuator sliders before flying.
Power servos from a separate BEC sized for them, not from the board's 5 V pins. Servos draw large, changing currents, and current on the board's 5 V rail disturbs the onboard compass (see Magnetometer).
Airspeed Sensor
An airspeed sensor is strongly recommended for fixed-wing flight. Supported connections:
- I2C sensors (MS4525DO, SDP3x, and others) on the External I2C connector (I2C2)
- DroneCAN airspeed sensors on a CAN port (
UAVCAN_SUB_ASPD= 1; see DroneCAN)
Calibrate it in Vehicle Setup → Sensors → Airspeed.
Setup Steps
- Select the airframe (Vehicle Setup → Airframe), for example Standard Plane or Flying Wing.
- Assign outputs and set the timer group protocols as above.
- Calibrate sensors, including airspeed.
- Set up radio, flight modes (at least Manual, Stabilized and Return) and the battery.
- Check control surface directions in Manual mode and in Stabilized mode (tilt the plane; the surfaces must counteract the tilt).
Tuning
PX4 includes fixed-wing autotune (FW_AT_APPLY). See Autotune and the PX4 fixed-wing tuning guide.
VTOL
VTOL frames (standard VTOL, tiltrotor, tailsitter) use the same firmware. A VTOL needs both multirotor motors and fixed-wing surfaces, so check the output count: eight outputs cover, for example, four lift motors, a pusher and three servos. DroneCAN ESCs or servos can add outputs. See the PX4 VTOL documentation.