# Lesson 2-2a Principles of Flight - PowerPoint PPT Presentation

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## Lesson 2-2a Principles of Flight

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

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Title: Lesson 2-2a Principles of Flight

1
Lesson 2-2aPrinciples of Flight
2
The Forces of Flight
3
• How many forces are present when an aircraft is
cruising at constant speed and altitude?
• a. 0
• b. 2
• c. 4
• d. 6

4
Lift
• 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

5
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

6
Airfoils
• Can be wings or propeller blades
• Parts of airfoil Include leading and trailing
edges, camber and chord line

7
Wind Tunnels, cont.
• The Wright Brothers tested more than 200 wing
shapes in a tunnel before the successful 1902
glider
• Researchers can carefully control airflow
conditions and measure the forces on an aircraft
model

8
Activity Bernoullis Principle in Action
• Lets do a quick experiment to demonstrate
Bernoullis Principle in action using a funnel
and a ping-pong ball

9
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

10
Critical Angle of Attack
• Point at which a plane stallsaround 15

Reproduced from NASA/Glenn Research Center
11
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
velocity
• To increase lift
• Increase aircrafts forward speed
• Increase airfoils angle of attack (up to stall
angle)
• Increase surface area of airfoil

Reproduced from NASA/Glenn Research Center
12
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

13
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

14
Airfoil Types, Purpose, and Function
• See handout of conventional airfoils

15
The Fuselage
• The fuselage is the aircraft body
• Fuselage vary in shape to fit the mission
• Fuselage must be strong enough to withstand
torque

Courtesy of USAF/CMSgt Gary Emery
16
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
17
Wing Angles
• Dihedral angles give aircraft roll stability and
level flight
• Large commercial airliner wings have dihedral
angles
• Fighter aircraft have anhedral angles

Modified from NASA/Glenn Research Center
18
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

19
The Role of Stabilizers and Rudders, cont.
• Rudder is the hinged piece on the vertical
stabilizer
• Lets pilot steer the aircraft by moving the tail
left or right
• Elevators are the hinged flaps on the horizontal
stabilizer
• Lets pilot steer the aircraft by moving the tail
up or down

20
The Positions of Flaps, Spoilers, and Slats on
Aircraft
• 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

21
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

22
Primary Flight Controls
• Pilot uses primary flight controls to control
aircraft yaw, pitch, and roll
• Rudders control yaw or side-to-side motion of
aircraft
• Elevators control pitch or up and down motion of
aircraft
• Ailerons control roll or banking of the wings

23
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)

24
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

25
Spoilers
• 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

26
Activity Airplane Parts and Functions
• Label the airplane parts
•
• Define their function in flight