E-flite T-34 Mentor 25 ePTS RTF manual - Manual (Page 11)

11 E-flite T-34 Mentor ARF Assembly Manual
 4. Slide the fin fully into position. Use two 3mm washers
and two 3mm locknuts to secure the fin. Tighten these
nuts down using an adjustable wrench.
 5. Align the control horn so it is 90 degrees to the rudder
as shown.
 6. Center the control horn vertically in the slot on the side
of the fuselage. Use a #2 Phillips screwdriver to tighten
the black screw against the rudder control rod. Use
threadlock on the screw to prevent it from vibrating loose.