Differential Spoilers

Usage

Normal Flying-wing aircraft uses two control surfaces as Elevons to control pitch and roll. In some cases, rudders are added to the winglets to control yaw. Differential spoiler takes advantage of splitting elevons to 4 independent control surfaces: normal elevon functions are reserved for pitch and roll control, but yaw control is done by using two surfaces on one side of the wing to create drag force thus controlling yaw motion. If calibrated correctly, it will ensure pilot has smooth yaw control during take-off and landing as well as compensation during turning (similar to differential aileron).

Left Yaw by inducing drag on left wing: Right Yaw by inducing drag on right wing:
4surfLeftYaw 4surfRightYaw

Preparation

To use differential spoiler function, the airframe is required to use have 4 control surfaces (2 on each wing).

Setup

Now setup your 4 channels using the SERVOn_FUNCTION parameters:

Function Name Function Number Description
Differential Spoiler Left 1 16 This should be set to the outer left servo
Differential Spoiler Right 1 17 This should be set to the outer right servo
Differential Spoiler Left 2 86 This should be set to the inner left servo
Differential Spoiler Right 2 87 This should be set to the outer right servo

You can adjust the direction of each servo using the SERVOn_REVERSED parameters, and swap channels to get the right movement direction for elevons and rudder.