ALLXF C-20T: A 46–49 g Three-Axis FPV Gimbal

The ALLXF C-20T is a three-axis gimbal for FPV aircraft, drones and RC vehicles. The basic polymer version weighs approximately 49 g, while the aluminum-magnesium version weighs approximately 46 g. It supports DJI and Walksnail digital cameras as well as 19 mm analog FPV cameras.

Unlike a typical action-camera gimbal, the C-20T is designed for small FPV cameras and integration into an RC control system. The camera can also be controlled by head movement using a compatible HeadTracker.

Three-axis stabilization

The C-20T uses a non-orthogonal three-axis mechanism designed to reduce size and weight while retaining compensation for movement on all three axes. It uses brushless motors described as having higher torque, although no comparison figure is provided.

The manufacturer also demonstrates the gimbal on fixed-wing aircraft during sharp turns and descents, where it is intended to help keep the horizon level. The result depends on the platform's movement and the limits of the stabilization system. During installation, builders should also allow for the possibility that the aircraft's structure or the camera itself may physically restrict some positions.

Compatible cameras

The C-20T supports the following FPV cameras and systems:

• DJI O4 Pro, DJI O4 and DJI O3
• Walksnail Avatar and Walksnail Moonlight
• Analog FPV cameras with a width of 19 mm

For DJI O4, the gimbal is mechanically prepared for that camera type, so a builder does not have to design a custom 3D-printed platform from scratch. Support for analog cameras also extends its usefulness to older or experimental builds.

HeadTracker and control interfaces

With a compatible HeadTracker, the gimbal moves as the pilot turns their head. This lets the user look around through the camera rather than only looking in the direction the aircraft is pointing.

The gimbal can be controlled via MAVLink, S.BUS, CRSF or PWM. MAVLink enables integration with autopilots and flight controllers, while S.BUS and CRSF are interfaces used with RC receivers. The choice of control method therefore depends on the equipment and wiring in the particular build.

Three stabilization modes

• Horizon Mode: The gimbal attempts to keep the image level. It can be useful for steadier video or inspection, though its ability to compensate for movement has limits.
• Pitch-lock Mode: Camera pitch remains controlled, while roll and yaw follow the platform's movement more closely. This mode may be useful for tracking a target.
• FPV Mode: The gimbal uses 3D follow behavior, so the image follows the aircraft's movement more closely. This gives a more natural feel for FPV flying.

Versions, power and integration

The basic polymer version weighs approximately 49 g. The alloy version, made from an aluminum-magnesium alloy, weighs approximately 46 g, making it slightly lighter. On a lightweight FPV aircraft, even a few grams can matter when planning the total weight of the build.

The listed power input range is approximately 7.4 to 26.4 V, allowing integration with different RC power systems. Before connecting it, check the requirements for the specific revision and the polarity in the manual.

ALLXF publishes firmware and developer files. Builders can use the gimbal model in an aircraft's CAD design before installation, for example to assess its placement and the clearance around the camera.

Who is the C-20T for?

The C-20T is likely to appeal to more experienced FPV builders who want a stabilized camera, head-tracking control or integration with their own control system. It could be used on a fixed-wing aircraft or RC car, for mapping, or for a cockpit-like flying perspective.

For a typical freestyle FPV quad, a gimbal may be unnecessary: a fixed camera gives the pilot a more natural sense of the aircraft's movement. In other builds, the C-20T's main appeal is its combination of low weight, support for multiple cameras and control options.