QuadPlane Auto Flap Not Deploying During Autonomous Flight

ArduPlane VTOL Plane
1

Has anyone successfully used automatic flaps on a QuadPlane? I am having an issue where the flaps work correctly when controlled manually, but they never deploy automatically during autonomous flight.

I am using a Cube Orange flight controller running ArduPlane. The flaps are configured as Auto Flap in the Servo Output settings.

I performed a ground test by assigning a flap channel to my transmitter, and both flap servos responded correctly. Therefore, the servo outputs, wiring, and mechanical operation appear to be working properly.

However, during autonomous flights, the flaps did not deploy. I tested both configurations of Flight Options Bit 15 (enabled and disabled), but the behavior was the same in both cases.

I also configured parameters such as:

  • FLAP_1_SPEED

  • FLAP_1_PERCNT

  • FLAP_2_SPEED

  • FLAP_2_PERCNT

The aircraft was flying below the configured FLAP_1_SPEED threshold at certain points, but the flaps still did not deploy.

One important detail is that I was not using a pitot tube / airspeed sensor during these flights. I am therefore wondering whether the automatic flap logic requires a valid airspeed measurement, or whether ArduPlane can use another airspeed estimate (such as GPS-derived groundspeed) for this function.

The aircraft is a QuadPlane, so I am also wondering whether the flap logic behaves differently during AUTO mode, VTOL operation, or the transition between VTOL and fixed-wing flight.

Could someone clarify the following?

  1. Does automatic flap deployment based on FLAP_1_SPEED require a valid airspeed sensor?

  2. If no airspeed sensor is installed, what value does ArduPlane use to determine whether the flap speed threshold has been reached?

  3. Does Flight Options Bit 15 affect the automatic flap logic in a QuadPlane?

  4. Are there any additional parameters or conditions that must be satisfied before Auto Flap outputs are activated?

  5. Which DataFlash log messages or parameters should I check to determine why the flap command was not generated?

If anyone has experienced a similar issue with QuadPlane automatic flaps, I would appreciate any advice or examples of a working configuration.

I can also provide the relevant parameter file and DataFlash log if needed.

2

Please share that flight log.

3

The flight dated 2026-08-07 17-16-16 was conducted with Bit 15 enabled, while the other flight was conducted with Bit 15 disabled.

4

Currently you need a airspeed sensor for flaps to work.