Extreme Flight 125" EXTRA 300 Assembly Manual page 8

Rudder preparation and installation
15. This step is also very important-please pay close attention. There are 2 sets of control
horns provided for the rudder. The larger horn set is to be used if you intend to use a pull-
pull set-up with the rudder servos mounted inside the fuselage under the canopy. If using 4
elevator servos it is recommended that you use the pull-pull option to help achieve proper
CG. A 5 inch servo arm is recommended for proper geometry.
The smaller horns are to be used if you use a direct drive push-pull linkage with 2 servos
mounted in the rear of the fuselage. This is the preferred method as it is much easier to set
up and provides a more direct and powerful means of rudder actuation. These horns are
the same as used for the elevators.