The operator manual designates the
channels as used with RC aircraft. In
the manual, the left stick up/down is
the Throttle on Channel 3. This is the
channel used to control the Sails.
In the manual, the right stick
left/right is the Aileron on Channel 1.
This is the channel used to control
the Rudder.
NOTE: The Rudder servo shown on the diagram is only for Airplanes, not Sailboats.
The operator manual can be found here: https://www.flysky-cn.com/fsi6