12. Alignment of Stabilizer.—Support the weight of the tail on the tail skid.
The rear edge of the stabilizer should be perfectly straight, and should be parallel with lateral axis of the machine.
Stand behind the center of the stabilizer, and align its rear edge on the leading edge of the upper plane by sighting. Tighten wires and safety turnbuckles.
13. Alignment of Elevator Flaps.—Set the elevator control in its mid-position. Adjust the elevator control wires until the flaps are in their neutral position and both are in the same plane. The wires should be just tight enough to eliminate any lost motion. Safety turnbuckles.
14. Alignment of Rudder.—Set the rudder control (wheel, foot pedals, or foot bar) in its mid-position. Adjust the rudder control wires until the rudder is in its neutral position. The control wires should be just tight enough to eliminate any lost motion. Safety the turnbuckles.
15. General.—All connections having been made, carefully go over each shackle, pin, and turnbuckle, and see that all pins are properly in place, all nuts on bolts tight and all cotter-pinned. Try out all controls for action and freedom of movement. See that no brace wires are slack, yet not so taut that when plucked they “sing.”
16. Overall Adjustments.—As a final check, the following overall measurements should be taken (see Fig. [39]).
The straight lines AC and BC should be equal to within ⅛ in. The point C is the center of the propeller, or in the case of the pusher the center of the nacelle. A and B are points on the main spar and must be at the same distance from the butt of the spar. They must not be merely the sockets of the outer struts as these may not be accurately placed. AC and BC must be taken from both top and bottom spars; two measurements on each side of the airplane.
Similarly FD and FE should be equal to within ⅛ in. F is the center of the fuselage or rudder post. D and E are points marked on both top and bottom rear spars just as A and B were marked on front spars.
If these measurements are not correct, it is probably due to some of the drift or antidrift wires being too tight or too slack. These must then be located and corrected.