LESSON: Elevators, Ailerons, and Rudder

OBJECTIVE:

To develop the students understanding of the function of the primary control surfaces

ELEMENTS:

 Axes of Rotation  Elevators  Ailerons  Rudder

SCHEDULE:

 20 Min Total

EQUIPMENT:

 Appropriate textbooks  Chalkboard & chalk  Model aircraft  Appropriate slides/Visual Aids

INSTRUCTORS ACTIONS:

 Discuss lesson objective

 Introduce the concept of control surfaces

 Discuss the axis of rotation: Longitudinal, Lateral, & Vertical  Discuss the primary control surfaces: Ailerons, Rudder, & Elevator  Ask pertinent questions to determine students understanding  Assign appropriate study material

STUDENTS ACTIONS:

 Listen, take notes, ask questions  Respond to instructors questions  Leave with a framework understanding of the subject

COMPLETEION STANDARDS:

The student should demonstrate adequate understanding of the function of the control surfaces by successfully completing an oral quiz or written exam Introduction

Attention/Motivation

In order for a pilot to be able to successfully fly an airplane s/he must understand how the flight control surfaces work to maneuver the airplane

Overview

 This lesson discusses the devices with which the pilot controls the aircraft, the Primary flight controls, and the axis about which the control surfaces rotate the airplane

DEVELOPMENT

 Flight Control surfaces move, by the pilot’s input, to deflect the air flowing past the aircraft.  This results in the attitude of the aircraft changing

Axis of Rotation

 3 Axis: Longitudinal, Lateral, & Vertical  The longitudinal axis runs from the front to back of the airplane  The aircraft rolls (nose rotates left and right with respect to the pilot) around the longitudinal axis  The lateral axis runs from the left to right of the airplane  The aircraft pitches (nose moves up and down with respect to the pilot) around the lateral axis  The vertical axis runs from the top to bottom of the airplane  The aircraft yaws (nose swings left and right with respect to the pilot) around the vertical axis

Primary control surfaces

 Ailerons, Rudder, & Elevator

Ailerons

 Ailerons control an airplane about its longitudinal axis - roll  Most light airplanes have two ailerons, one on the trailing edge of each wing

 Pilot controls them through the use of a yoke or stick, connected to the ailerons by cables and pulleys

 They move in opposite directions  Change the lift on the wing to move it up or down and roll the airplane  Adverse yaw – Downward deflected aileron produces more lift and therefore more drag, this causes the airplane to yaw in the opposite direction of the roll

 Differential-Type & Frise-Type Ailerons help to reduce adverse yaw

 Differential-Type Ailerons - raise an aileron more than one is lowered  Frise-Type Ailerons - use a offset hinge to project the leading edge of the raised aileron into the airflow, this counteracts the induced drag from the lowered aileron

Rudder

 The rudder controls the airplane about its vertical axis - yaw  Most light airplanes have one rudder, located on the trailing edge of the vertical fin  Pilot controls the rudder through the use of foot pedals, connected to the rudder by bell cranks, cables and pulleys  The Rudder does not turn the airplane, only yaws it  Rudder is used in conjunction with the ailerons for properly turning the airplane

Elevator

 The elevator controls the airplane about its lateral axis – pitch  Main purpose of the elevator is to change the wings angle of attack  Most light airplanes have one elevator, located on the trailing edge of the Horizontal stabilizer  Some aircraft (Piper Products) use a stabilator, or movable horizontal stabilizer  Pilot controls them through the use of a yoke or stick,, connected to the elevator by bell cranks, cables and pulleys

 The horizontal stabilizer has a negative angle of attack to provide downward force

 The elevator moves up to increase this downward push and move the nose up, and therefore increase the wings angle of attack  The elevator moves down to decrease this downward push and move the nose down, and therefore decrease the wings angle of attack

CONCLUSION

 3 Axis: Longitudinal, Lateral, & Vertical  The flight controls move the airplane about these axis  Ailerons, on the trailing edge of the wings, control an airplane about its longitudinal axis – roll  The rudder, on the trailing edge of the vertical stabilizer, controls the airplane about its vertical axis – yaw  The elevator, on the trailing edge of the horizontal stabilizer, controls the airplane about its lateral axis – pitch

QUESTIONS