The Axes Of An Airplane

The axes of an aircraft are three imaginary lines that pass through an aircraft’s CG. The axes can be considered as imaginary axles around which the aircraft turns. The three axes pass through the CG at 90° angles to each other. The axis from nose to tail is the longitudinal axis, the axis that passes from wingtip to wingtip is the lateral axis, and the axis that passes vertically through the CG is the vertical axis. Whenever an aircraft changes its flight attitude or position in flight, it rotates about one or more of the three axes.

 

  LONGITUDINAL AXIS :

The longitudinal axis extends lengthwise through the fuselage from the nose to the tail. Movement of the airplane around the longitudinal axis is known as roll and is controlled by movement of the ailerons. To move the ailerons, the pilot turns the control wheel either clockwise or counter clockwise (or moves the control stick either right or left). This action lowers the aileron on one wing and raises the aileron on the other wing. The downgoing aileron increases the camber of its wing, producing more lift and the wing rises. The upgoing aileron spoils the airflow on its wing, decreases the lift and the wing descends. The airplane rolls into a turn.

THE LATERAL AXIS :

The vertical or normal axis passes vertically through the center of gravity. Movement of the airplane around the vertical axis is yaw and is controlled by movement of the rudder. Pressure applied to the left rudder pedal, for example deflects the rudder to the left into the airflow. The pressure of the airflow against the rudder pushes the tail to the right. The nose of the airplane yaws to the left.
 

 THE VERTICAL OR NORMAL AXIS :

The vertical or normal axis passes vertically through the center of gravity. Movement of the airplane around the vertical axis is yaw and is controlled by movement of the rudder. Pressure applied to the left rudder pedal, for example deflects the rudder to the left into the airflow. The pressure of the airflow against the rudder pushes the tail to the right. The nose of the airplane yaws to the left.

There is a distinct relationship betweenmovement around the vertical and longitudinal axes of an airplane (i.e. yaw and roll). When rudder is applied to effect a yaw, for example, to the right, the left wing (on the outside of the turn) moves faster than the inside wing, meets the relative airflow at a greater angle of attack and at greater speed and produces more lift.. The use of rudder, therefore, along with aileron can help to raise the wing and produce a better coordinated turn.

 
In a roll, the airplane has a tendency to yaw away from the intended direction of the turn. This tendency is the result of aileron drag and is called adverse yaw. The upgoing wing, as well as gaining more lift from the increased camber of the downgoing aileron, also experiences more induced drag. The airplane, as a result, skids outward on the turn. Use of rudder in the turn corrects this tendency.

Do you like this post? Please link back to this article by copying one of the codes below.

URL: https://basicaerospace.blogspot.com/2013/01/the-axes-of-airplane.html HTML link code: <a href="https://basicaerospace.blogspot.com/2013/01/the-axes-of-airplane.html">The Axes Of An Airplane</a> BB (forum) link code: [url=https://basicaerospace.blogspot.com/2013/01/the-axes-of-airplane.html]The Axes Of An Airplane[/url]