E-flite Brio 10 ARF - Manual (Page 46)

 4. Lightly sand both sides of the middle section of
the plastic rudder control horn before installing so
the CA wicks better. Install the rudder control horn
for the rudder using medium CA. Square the horn
to the control surface.
Note: The control horn has ears that will allow it
to only slide into the rudder from one direction.
These ears rest against the side of the rudder
when installed correctly.
 5. Mount the rudder servo inside the fuselage using
the hardware provided with the servo. Install
two micro control connectors into a long servo
arm. Secure them using the control connector
backplates. With the radio system on, center the
rudder trim and sub trim, then install the servo
arm on the rudder servo.
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