E-flite Extra 260 3D Profile - Manual (Page 23)

 2. Install the rudder and elevator micro control horns
at this time as well. Make sure the rudder horn
extends opposite of the elevator horn.
 3. Remove the servo arms from the four servos.
Drill a 1/16" (1.5mm) hole in the end of all four
of the servo arms.
Note:.We.then.suggest.using.the.longest.servo.
arms.available.for.your.servo.to.help.achieve.
maximum.control.throws.for.3D.flying.
3