# Aircraft Motion and Control

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Aircraft Motion and Control
Objective: Know basic aircraft motion and how it is controlled. 1. Identify the axes of rotation. 2. Identify the effects of ailerons and elevators on flight. 3. Identify the effects of flaps on flight. 4. Identify the effects of the rudder on flight 5. Identify the effects of spoilers on flight. Lesson Objective: Know aircraft motion and how it is controlled. Samples of Behavior/Main Points 1. Identify the axes of rotation. 2. Identify the effects of flaps on flight. 3. Identify the effect of slats on flight. 4. Identify the effects of spoilers on flight. 5. Identify the effects of drag on flight. 6. Describe the elements of controlled flight.

Bernoulli Principle As the air velocity increases, the pressure decreases; and as the velocity decreases, the pressure increases

The Axes of Rotation PITCH ROLL YAW

The Axes of Rotation Longitudinal Axis
Running from the tip of the nose to the tip of the tail. This axis can be thought of as a skewer which turns either right or left and causes everything attached to it to turn. Longitudinal Axis Running from the tip of the nose to the tip of the tail is the longitudinal axis of an airplane. This axis can be thought of as a skewer which turns either right or left and causes everything attached to it to turn. The wings, tail, and landing gear all move about the longitudinal axis when movement is initiated.

The Axes of Rotation Longitudinal Axis
The cause of movement or roll about this axis (roll axis) is the action of the ailerons. The cause of movement or roll about this axis (or roll axis) is the action of the ailerons. Ailerons are attached to the wing and to the control column in a manner that ensures one aileron will deflect downward when the other is deflected upward.

The Axes of Rotation Lateral Axis
An imaginary rod, running from one wing tip through the other wing tip, forms an airplane’s lateral axis. Another name for the lateral axis is the pitch axis. The flaps and elevators can be deflected up or down as the pilot moves the control column backward or forward. Flaps Elevators The Axes of Rotation Lateral Axis Another imaginary rod, running from one wing tip through the fuselage and exiting the other wing tip, forms an airplane's lateral axis. The lateral axis theoretically allows the airplane to spin around and around its wings. This cannot happen because the wings would not produce enough lift. Another name for the lateral axis is the pitch axis. The airplane is actually caused to pitch its nose upward or downward about the lateral axis. The elevator can be deflected up or down as the pilot moves the control column backward or forward. Movement backward on the control column (or stick) moves the elevator upward. This changes the shape of the stabilizer airfoil so that the direction of lift on the tail surface is down. This pulls everything aft of the airplane's lateral axis down with it and causes everything forward of the lateral axis to pitch upward. This movement increases the wings' angle of attack, which in turn creates more lift, and the airplane climbs. Deflection of the elevator downward creates a high lift condition on the stabilizer-elevator airfoil and the tail is raised. This pitches the portion forward of the lateral axis downward and the airplane dives.

Flaps The flaps are attached to the trailing edge of the wing. In cruising flight, the flaps simply continue the streamline shape of the wing’s airfoil. When flaps are lowered either partially or fully, lift and drag are increased. Flaps The flaps are attached to the trailing edge of the wing. In cruising flight, the flaps simply continue the streamline shape of the wing's airfoil. On small airplanes, the flaps can be "lowered" as much as 40o to the cord. When flaps are lowered either partially or fully, lift and drag are increased. Pilots use the flaps during certain takeoff conditions and during most landing situations.

Flaps Flaps increase the camber of the wing airfoil for the portion of the wing that it is attached. This causes the air to speed up over the wing section where the most lift is created. On the underside of the wing, dynamic lift is increased. Using flaps when taking off helps the airplane get off the ground in a shorter distance. Flaps increase the camber of the wing airfoil for the portion of the wing that it is attached. It does not affect the remainder of the wing. When the flaps are lowered air flowing over the top of the wing has to travel farther. This causes the air to speed up, particularly over the wing section where the most lift is created. On the underside of the wing, dynamic lift is increased because there is now more surface area exposed to the impact of the relative wind. On the negative side of this situation is the drag produced by the flap (or flaps). Anything that obstructs the airflow certainly increases drag. The net effect of the increased lift and drag when the flaps are lowered is without an increase in power to compensate for the additional drag, an airplane will descend much more steeply than possible without flaps, and the increased lift allows slower flight because the stall speed is decreased. When landing, flaps permit the steep descent that may be necessary to land on a short runway that has an obstruction along the landing path. The flaps also lower the stall speed. This allows a pilot to touch down at a slower groundspeed upon landing that leads to less wear and tear on all parts of the airplane. Using flaps when taking off helps the airplane get off the ground in a shorter distance. This might be desired when the runway is short or a shorter distance takeoff is necessary. It also helps when taking off from a soft or muddy field as it gets the airplane's weight off the landing gear as quickly as possible to reduce "mud drag" on its wheels.

The Axes of Rotation Vertical Axis
An imaginary rod or axis which passes through the meeting point of the longitudinal and lateral axes. It is also referred to as the “yaw” axis. The airplane turns about this axis in a side-to-side direction. The airplane’s rudder is responsible for the movement about this axis. The Axes of Rotation Vertical Axis An imaginary rod or axis which passes through the meeting point of the longitudinal and lateral axes. It is also referred to as the "yaw" axis. The airplane turns about this axis in a side-to-side direction. The airplane's nose is made to point in a different direction when the airplane turns about this particular axis. The airplane's rudder is responsible for the movement about this axis. The cause of this movement is the change in the direction of lift generated by an airfoil. When a pilot presses on the rudder pedals, the rudder is deflected from a neutral or streamline position with the vertical stabilizer. The deflected rudder forms a curved or cambered airfoil surface, which on one side generates induced lift while on the other side dynamic lift. Rudder controls are rigged so that the rudder moves toward the direction of the rudder pedal that is pressed. This causes the airplane's nose to point toward the direction of the rudder pedal being pressed.

Rudder Located on the Vertical Stabilizer (tail)
Controls the aircraft’s yaw Right Rudder = Right Yaw Left Rudder = Left Yaw Flaps The flaps are attached to the trailing edge of the wing. In cruising flight, the flaps simply continue the streamline shape of the wing's airfoil. On small airplanes, the flaps can be "lowered" as much as 40o to the cord. When flaps are lowered either partially or fully, lift and drag are increased. Pilots use the flaps during certain takeoff conditions and during most landing situations.

Spoilers Spoilers work to destroy lift.
Spoilers are found on various aircraft from the jet airliner to the sailplane. On the jet airliners, spoilers are hinged so that their aft portion is tilted upward into the smooth airflow. Spoilers Spoilers work to destroy lift. This is the origin of the name spoiler; a spoiler spoils lift. Spoilers are found on various aircraft from the jet airliner to the sailplane. It is found somewhere along the top of the wing and it will be located along a line on the airfoil where its deployment will be most effective. They fit into, or flush with; the upper cambered surface of the airfoil, and located along a line from wing root to wing tip (the exact placement will depend on the airfoil design). The size will vary according to how much lift is to be "spoiled." On the jet airliners, spoilers are hinged so that their aft portion is tilted upward into the smooth airflow. Many of the sailplane types are designed to thrust straight up from the wing's surface. Both arrangements of spoilers destroy flow of air for a portion of the wing and thereby reduce a certain amount of induced lift. An airplane, such as an airliner, can thus fly at a safe airspeed while reducing some of the induced lift. The result is a steep descent for landing.

So Lets Put It all Together….

Review Which is not a primary axis associated with basic aircraft motion? A. Longitudinal Axis B. Lateral Axis C. Vertical Axis D. Diagonal Axis

Review Affecting movement along the Longitudinal Axis, which basic aircraft control surface results in the aircraft rolling? A. Ailerons B. Flaps C. Elevators D. Rudder

Review True or False? Extending flaps, increases both lift as well as drag? A. True B. False

Review If an aircraft rudder was positioned as in the picture below, which direction would the aircraft begin to yaw? A. Left B. Right Vertical Stabilizer (Tail) Rudder

Aircraft Motion and Control
Objective: Know basic aircraft motion and how it is controlled. 1. Identify the axes of rotation. 2. Identify the effects of ailerons and elevators on flight. 3. Identify the effects of flaps on flight. 4. Identify the effects of the rudder on flight 5. Identify the effects of spoilers on flight. Lesson Objective: Know aircraft motion and how it is controlled. Samples of Behavior/Main Points 1. Identify the axes of rotation. 2. Identify the effects of flaps on flight. 3. Identify the effect of slats on flight. 4. Identify the effects of spoilers on flight. 5. Identify the effects of drag on flight. 6. Describe the elements of controlled flight.

OK….got the basics? Good! Out to the Flight Line…
NERVOUS YET? ……

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