Abstract: An elevator variable feel unit for aircraft pilot control. The variable feel unit has a single cam and a roller unit. The cam attaches by a spline to the input shaft and input crank of the feel unit. The input crank, connected to the control column torque tube, turns the shaft and the cam. A cam follower arm assembly has a roller that causes a cam follower arm to pivot as the cam is pivoted due to movement of the control column. Two base feel centering springs between the cam follower arm and a fixed point to keep the roller on the cam, and provide the base feel force and a centering function. In a base feel position, the preload on the base feel spring keeps the variable feel unit in a detent position. The variable feel spring has a minimum preload and does not add to the feel at low airspeed. When the control column is moved, the movement causes an increase in the extension of the base feel springs, thus increasing the feel forces at the column.

Abstract: A rudder control linkage having thermal compensation features employs a stationary thermal compensation rod, a lever with a fixed pivot, a reversing link with a movable pivot, a summing link, pilot and yaw damper input rods, and output rods. In an airplane having a fin and a rudder, the linkage is utilized to cancel undesired yaw inputs to the rudder caused by fin bending and differential thermal expansion which, if not corrected, would deleteriously affect airplane trim.