Here is a view looking back from the cockpit inside the tail of the plane. You can see the welded steel tubing structure of the fuselage with lots of cross bracing to make good strong triangles. The shoulder harness is in the top of the picture at the center. It attaches to the frame with two wires. The rudder control cables pass through the rectangular frame either side of the center of the photo. The other cable on the right hand side is the elevator trim control. The solid black rod extending from the bottom toward the center of the frame is the elevator control.