However, a trim crank may be found in some airplanes. The cockpit control includes a tab position indicator.Trimming the elevator for hands off flight
When the control column is pulled back, it raises the stabilator’s trailing edge, rotating the airplane’s nose up. Pushing the control column forward lowers the trailing edge of the stabilator and pitches the nose of the airplane down. Without an anti servo tab, the airplane would be prone to over controlling from pilot-induced control inputs.Stabilator is essentially a one-piece horizontal stabilizer
Stabilator•Antiservo tabs instead of moving in the opposite direction of the surface, they move in the same direction as the trailing edge of the stabilator. •In addition to decreasing the sensitivity of the stabilator, an antiservo tab also functions as a trim device to relieve control pressure and maintain the stabilator in the desired position•The fixed end of the linkage is on the opposite side of the surface from the horn on the tab; when the trailing edge of the stabilator moves up, the linkage forces the trailing edge of the tab up.
Anti-servo tabs •An anti-servo tab works in the opposite way to a servo tab. It deploys in the same direction as the control surface, making the movement of the control surface more difficult and requires more force applied to the controls by the pilot. •This may seem counter-productive, but it is commonly used on aircraft where the controls are too light or the aircraft requires additional stability in that axis of movement. •The anti-servo tab serves mainly to make the controls heavier in feel to the pilot and also to increase stability .An anti-servo tab on the elevator of an American Aviation AA-1 Yankee
Rather than using a movable tab on the trailing edge of the elevator, some airplanes have an adjustable stabilizer. With this arrangement, linkages pivot the horizontal stabilizer about its rear spar. This is accomplished by use of a jackscrew mounted on the leading edge of the stabilator.Common on large airline aircraftAdjustable Stabilizer
Definition:Simultaneous motion about two axes of the aircraft-Longitudinal and vertical-one is stronger than the other.Dutch roll
Dutch RollDutch roll is caused by an aircraft’s tendency to sideslip slightly when the aircraft yaws. One wing yawing forward in this situation changes the effective span between left and right wings. The wing yawed forward momentarily creates more lift than the one of the other side. The result is that the forward wing rises and starts a rolling movement. The problem is aggravated by the fact that the forward wing, due to its increased lift, also has more drag, pulling that wing back once again and starting an oscillation in the other direction.
Dutch RollThe term Dutch rollrefers to a tendency for an aircraft to roll whenever there is yaw.