ArduPilot Plane

Summary¶

ArduPilot Plane is the fixed-wing variant of the ArduPilot autopilot firmware, running on the same Matek H7A3-WING flight controller used by libdrone Wing. Where ArduPilot Copter manages multirotor attitude and position, ArduPilot Plane manages forward flight speed (airspeed), altitude, and navigation for fixed-wing and flying-wing aircraft. Its core flight management system is TECS — Total Energy Control System — which coordinates throttle and pitch to maintain the target airspeed and altitude simultaneously. Configuration for a flying wing (elevon mixing) differs from conventional aircraft (separate elevator and ailerons) and must be set correctly before any flight.

Concept¶

TECS — Total Energy Control System¶

A multirotor controls altitude directly: increase throttle to climb, decrease to descend. A fixed-wing cannot do this cleanly — increasing throttle accelerates the aircraft as well as climbing, and pitching up to climb bleeds speed. The two control inputs (throttle and pitch) couple.

TECS decouples them by managing total energy: the sum of potential energy (altitude) and kinetic energy (speed). When the aircraft needs to climb (increase potential energy), TECS increases throttle to add total energy and uses pitch to allocate it between altitude and speed. When the aircraft needs to descend, TECS reduces throttle and pitches to exchange altitude for speed while maintaining the target airspeed.

The result is that the operator specifies a target airspeed and altitude; TECS handles the throttle and pitch outputs to achieve both. This is what makes autonomous survey grid flights stable: altitude hold in fixed-wing is indistinguishable from altitude hold in a multirotor from the operator's perspective, even though the control law is completely different.

Flying wing configuration¶

A flying wing (Skywalker X8, Mini Talon V2) has no separate elevator or ailerons — control surfaces called elevons combine both functions. ArduPilot Plane must be configured for the correct airframe type:

FRAME_CLASS,2 ; Flying wing

With this setting, ArduPilot outputs elevon mixing automatically: the elevator channel drives both surfaces in the same direction (pitch), and the aileron channel drives them in opposite directions (roll). No manual mixing is required in the transmitter.

Auto-takeoff and auto-land¶

ArduPilot Plane supports auto-takeoff from a hand launch. The aircraft is armed with throttle at idle, hand-launched, and immediately switches to FBWA (Fly-By-Wire-A) or TAKEOFF mode — climbing at the configured pitch angle until the target altitude is reached, then transitioning to AUTO mode for the mission.

Auto-land uses a landing waypoint in the mission: the aircraft flies a descending approach to the landing point, then flares (pitch up, throttle cut) at the configured flare altitude. For Wing's field deployments, a belly landing on flat ground or hand-catch is the standard recovery method.

Reference¶

Key flight modes (Wing): - MANUAL: direct stick-to-surface passthrough, no stabilisation - FBWA (Fly-By-Wire-A): attitude stabilised, pilot commands bank angle and pitch - LOITER: GPS circle around a point at constant altitude - AUTO: execute waypoint mission - RTL: return to launch GPS coordinate and land

Procedure¶

Initial fixed-wing configuration (flying wing)¶

1. Flash ArduPilot Plane MatekH7A3-WING target via STM32CubeProgrammer.
2. Connect QGroundControl. Set FRAME_CLASS=2 (flying wing).
3. Calibrate accelerometer (6-position, same as Copter).
4. Calibrate compass (same as Copter).
5. Calibrate RC. Verify elevon surfaces move correctly: right stick right → right surface down, left surface up. If reversed, adjust RCMAP or reverse the relevant output channel.
6. Set TECS parameters for the chosen airframe (start with defaults; adjust after maiden flight based on cruise behaviour).
7. Configure auto-takeoff: set TKOFF_ALT=30, verify TAKEOFF mode in flight mode menu.
8. Verify RTL altitude is above terrain and obstacles in the survey area.

Rationale¶

ArduPilot Plane was selected over iNAV for Wing for the same reasons ArduPilot Copter was selected for Bandit and Ghost: the largest community-validated parameter set for the H7A3 target, and the most complete QGroundControl integration. iNAV is a capable fixed-wing firmware but its GCS integration is less mature and its TECS implementation is less thoroughly documented for survey applications. Maintaining a single autopilot ecosystem (ArduPilot) across Bandit, Ghost, and Wing reduces the operator's cognitive load: QGroundControl, mission planning workflow, and failsafe logic are the same across all three platforms.

Connections¶

yaml requires: - [fixed-wing-fundamentals](<./fixed-wing-fundamentals.md>) - [ardupilot-copter](<./ardupilot-copter.md>) - [gnss-gps](<./gnss-gps.md>) related: - [wing-variant](<./wing-variant.md>) - [qgroundcontrol](<./qgroundcontrol.md>) - [elrs-mavlink-mode](<./elrs-mavlink-mode.md>) - [closed-loop-control](<./closed-loop-control.md>) leads_to: - [qgroundcontrol](<./qgroundcontrol.md>) - [wildlife-survey-operations](<./wildlife-survey-operations.md>)