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Lesson 2-2a Principles of Flight


Lesson 2-2a Principles of Flight – PowerPoint PPT presentation

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Title: Lesson 2-2a Principles of Flight

Lesson 2-2aPrinciples of Flight
The Forces of Flight
  • How many forces are present when an aircraft is
    cruising at constant speed and altitude?
  • a. 0
  • b. 2
  • c. 4
  • d. 6

  • Lift is produced almost entirely by moving air
    over and under the wings
  • The profile of a wing is called an airfoil
  • Changing the airflow on the surface of the
    airfoil (or wing) will increase or decrease the
    amount of lift

Bernoullis Principle
  • Faster airflow causes a decrease in air pressure
  • Air flowing over the curved upper surface of a
    wing speeds up
  • Increase in speed reduces pressure above the wing
    and produces the upward lifting force

  • Can be wings or propeller blades
  • Parts of airfoil Include leading and trailing
    edges, camber and chord line

Wind Tunnels, cont.
  • The Wright Brothers tested more than 200 wing
    shapes in a tunnel before the successful 1902
  • Researchers can carefully control airflow
    conditions and measure the forces on an aircraft

Activity Bernoullis Principle in Action
  • Lets do a quick experiment to demonstrate
    Bernoullis Principle in action using a funnel
    and a ping-pong ball

Effect of Angle of Attack on Flight
  • If a plane alters pitchthe up and down movement
    of the planes nosethe angle of attack on its
    wings will change
  • As angle of attack increases, wings generate more
    lifting force

Critical Angle of Attack
  • Point at which a plane stallsaround 15

Reproduced from NASA/Glenn Research Center
How Lift is Generated
  • Air flows over top of wing reducing pressure on
    top surface relative to bottom surface of wing
  • Lift depends on aircrafts shape, size, and
  • To increase lift
  • Increase aircrafts forward speed
  • Increase airfoils angle of attack (up to stall
  • Increase surface area of airfoil

Reproduced from NASA/Glenn Research Center
Airfoil Camber
  • The curve in an airfoil is the camber
  • In most airfoils the upper surface curves more
    than the lower surface
  • Airfoils thickness is the maximum distance
    between the upper and lower wing surfaces

Airfoil Types, Purpose, and Function
  • Aircraft weight, speed, and purpose determine
    wings shape
  • Streamlined airfoils dont create enough lift
  • Teardrop shaped airfoils have no lift at zero
    angle of attack

Airfoil Types, Purpose, and Function
  • See handout of conventional airfoils

The Fuselage
  • The fuselage is the aircraft body
  • Fuselage vary in shape to fit the mission
  • Fuselage must be strong enough to withstand

Courtesy of USAF/CMSgt Gary Emery
Wing Position and Parts
  • Wing position depends on aircrafts mission
  • Main internal parts are spars, ribs and stringers
  • Fuel tanks usually part of wing

Reproduced from US Department of
Transportation/Federal Aviation Administration
Wing Angles
  • Dihedral angles give aircraft roll stability and
    level flight
  • Large commercial airliner wings have dihedral
  • Fighter aircraft have anhedral angles

Modified from NASA/Glenn Research Center
The Role of Stabilizers and Rudders
  • Stabilizers are on the aircrafts tail
  • Stabilizers keep aircraft stable so it can
    maintain straight flight path
  • Vertical stabilizer prevents the nose of plane
    from roving side to size
  • Horizontal stabilizer keeps plane from bobbing up
    and down

The Role of Stabilizers and Rudders, cont.
  • Rudder is the hinged piece on the vertical
  • Lets pilot steer the aircraft by moving the tail
    left or right
  • Elevators are the hinged flaps on the horizontal
  • Lets pilot steer the aircraft by moving the tail
    up or down

The Positions of Flaps, Spoilers, and Slats on
  • Flaps are hinged device at wings trailing edge
    that produces lift
  • Spoiler is small, flat plate that attaches the
    tops of wings it increases drag
  • Slat is moveable, hinged parts that pivot down to
    generate more force

Primary and Secondary Controls
  • Primary Controls make aircraft controllable and
    safe to fly
  • Rudders, elevators, and ailerons
  • Secondary controls let the pilot maintain more
    control over aircrafts performance
  • Flaps, slats, and spoilers

Primary Flight Controls
  • Pilot uses primary flight controls to control
    aircraft yaw, pitch, and roll
  • Rudders control yaw or side-to-side motion of
  • Elevators control pitch or up and down motion of
  • Ailerons control roll or banking of the wings

How Ailerons Work
  • Aileron is a small hinged section on the outboard
    portion of each wing
  • Ailerons operate in opposite direction on the
    wings, causing one to increase lift (point
    aileron down), one to decrease lift (point
    aileron up)

Secondary Flight Controls
  • Used primarily in more challenging flight
    conditions where low speeds are required
    (take-off and landing)
  • Flaps are on trailing edge of wings and
    increase/decrease lift and drag on both wings at
    the same time
  • Slats are on the leading edge of the wings and
    also increase/decrease lift and drag on both
    wings at the same time
  • Spoilers reduce lift and increase drag and can
    be used on both wings at same time or on one wing
    and not the other

  • Spoilers are small, flat plates that attach to
    the tops of the wings with hinges
  • Raising spoilers on both wings slows aircraft in
    any phase of flight
  • Raising spoilers on only one wing causes a
    rolling motion

Activity Airplane Parts and Functions
  • Label the airplane parts
  • Define their function in flight
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