5/11/01

Pusher planes have a tendency to shake their tails due to the ragged airflow off the fuselage. This turbulent air is the source for slight shakes in the tail surfaces. To totally omit the effect requires the fuselage to be truly streamlined. This presents problems for planes like the S-12XL or S-12S, since they are side by side seating, and therefore too short in length to have the magic three to one ratio of a streamline body.

Over the years we have tried various ways of tricking the air into acting like it is flowing over a longer streamlined body. The addition of the flow fence was a major improvement. Further improvement can be realized with the installation of an elevator push pull tube guide. Placed as near to the end of the elevator yoke as possible, the guide eliminates the side-to-side motion inherit to the yoke and tube assembly.

All that is required is a few hours of wrench time to remove the tail and rivet the guide to the front side of the tail boom extension. A kit is available from our parts department with install instructions. Price $10.00 Call 785-625-6346 and order part number KPCS0203.

Installation Instructions

1. Remove the tail by un-bolting the vertical fin, tail boom extension, rudder cables, lower tail cables and elevator yoke from the push pull tube. It is not required to remove the horizontal tail from the vertical. Hint: Hang the entire assembly from the rafters or a cherry picker while installing the guide. See figure 2.
2. With the tail removed, place the guide on the front side of the tail boom extension. File as required to make the guide position properly on the extension. Locate drill and rivet the guide in place. See figure 1.
3. Install the tail assembly to the plane. Slip elevator push pull tube through the slot in the guide and bolt in yoke.
4. Connect all bolts, cables and check motion of the elevator to verify freedom of travel.
5. Double-check all connections and range and freedom of controls before flying. The guide should dampen the elevator's tendency to move, this will provide a smoother feel at all speeds, enjoy!