I am configuring PX4 for a V-tailed fixed-wing aircraft without ailerons. I have not succeeded at finding any online guidance for this. It is also noteworthy that QGC 5.08 and 5.10 are not showing an actuators/mixer/allocator tab on the Vehicle Configuration page. This PX4 documenation suggests I should expect to find one.
Here are the settings I have created:
- CA_SV_CS_COUNT 2
- CA_SV_CS0_TYPE 7/Left V-Tail
- CA_SV_CS0_TRQ_P 1
- CA_SV_CS0_TRQ_R 1
- CA_SV_CS0_TRQ_Y 1
- CA_SV_CS1_TYPE 8//Right V-Tail
- CA_SV_CS1_TRQ_P -1
- CA_SV_CS1_TRQ_R 1
- CA_SV_CS1_TRQ_Y 1
- CA_SV_CS2_TYPE 0/Not Set
- CA_SV_CS2_TRQ_P 0
- CA_SV_CS3_TYPE 0/Not Set
- CA_SV_CS3_TRQ_Y 0
- PWM_MAIN_FUNC2 201/Servo 1
- PWM_MAIN_FUNC3 101/Motor 1
- PWM_MAIN_FUNC4 202/Servo 2
Am I barking up the right tree?
Is there any guidance for PID tuning on a rudder/elevator only airframe?
Is there a better place to post this question?
That’s not expected. Did you select the generic plane airframe? And are you using a recent PX4?
About the config: if you only have 2 servos but want to control roll, pitch and yaw with them you’ll likely not get a good result, because it’s mathematically impossible to allocate the correct torques. If your airframe is stable in yaw I would give up the control over the yaw axis (_Y to 0).
What you likely need though is to give up control over roll, and steer the plane through skid to turn. Requires a stable roll axis (needs dihedral), and the current PX4 guidance does not work with it (it only does bank to turn).
I am using PX4 version 1.17. Some research suggests that there might be some missing meta data files in the Holybro Kakute H7 support that is needed by QGC?
I captured the following log from QGC that might mean more to others than it does me:
2026-08-12T11:57:48.310 [I] default: qrc:/qml/QGroundControl/PlanView/HomePositionMapVisual.qml: Object or context destroyed during incubation (HomePositionMapVisual.qml)
2026-08-12T11:57:50.336 [W] Utilities.QGCFileDownload: Download error: "File not found (404)"
2026-08-12T11:57:50.605 [W] Utilities.QGCFileDownload: Download error: "File not found (404)"
2026-08-12T11:57:50.714 [W] Utilities.QGCFileDownload: Download error: "File not found (404)"
2026-08-12T11:57:50.714 [W] ComponentInformation.RequestMetaDataTypeStateMachine: COMP_METADATA_TYPE_ACTUATORS : failed to load metadata (primary and fallback) https://px4-travis.s3.amazonaws.com/Firmware/main/holybro_kakuteh7-wing_default/actuators.json.xz (RequestMetaDataTypeStateMachine.cc:445)
2 channel (plus throttle) is not an unusual configuration. The aircraft does have dihedral and has already flown manually and with Ardupilot. However, there are reasons for moving to PX4.
Due to the difference in response frequency, it seems problematic. Specifically, a complete absence of yaw damping will likely result in poor results.
It seems impossible that I’m the first to try to use PX4 on a “rudder” and dihedral aircraft?
