Air, Aerodynamics and Flight Review Booklet

Curriculum ObjectivesTopic A: Air and AerodynamicsOverviewStudents explore the characteristics of air and the interaction between moving air and solids. They learn that air is a compressible fluid, that it is composed of many gases, and that moving air can support solid materials in sustained flight. By studying birds and airplanes, they learn a variety of adaptations and designs that make flight possible and that provide for propulsion and control.General Learner ExpectationsStudents will:6–5 Describe properties of air and the interactions of air with objects in flight.Specific Learner ExpectationsStudents will:1. Provide evidence that air takes up space and exerts pressure, and identify examples of these properties in everyday

applications.2. Provide evidence that air is a fluid and is capable of being compressed, and identify examples of these properties in

everyday applications.3. Describe and demonstrate instances in which air movement across a surface results in lift Bernoulli’s principle.4. Recognize that in order for devices or living things to fly, they must have sufficient lift to overcome the downward force

of gravity.5. Identify adaptations that enable birds and insects to fly.6. Describe the means of propulsion for flying animals and for aircraft.7. Recognize that streamlining reduces drag, and predict the effects of specific design changes on the drag of a model

aircraft or aircraft components.8. Recognize that air is composed of different gases, and identify evidence for different gases. Example evidence might

include: effects on flames, the “using up” of a particular gas by burning or rusting, animal needs for air exchange.

Topic B: FlightOverviewStudents apply their knowledge of aerodynamics to design, build and test a variety of flying devices. In constructing models, students develop a basic design, then build it, test it, and solve the problems that inevitably arise. Through teamwork they learn that planning, communication, cooperation and flexibility are important to the overall result, even though parts of a task can be worked on individually. In the process, students learn about the parts of an aircraft, their role in controlled flight and the differences between aircraft and spacecraft.General Learner ExpectationsStudents will:6–6 Construct devices that move through air, and identify adaptations for controlling flight.Specific Learner ExpectationsStudents will:1. Conduct tests of a model parachute design, and identify design changes to improve the effectiveness of the design.2. Describe the design of a hot-air balloon and the principles by which its rising and falling are controlled.3. Conduct tests of glider designs; and modify a design so that a glider will go further, stay up longer or fly in a desired

way; e.g., fly in a loop, turn to the right.4. Recognize the importance of stability and control to aircraft flight; and design, construct and test control surfaces.5. Apply appropriate vocabulary in referring to control surfaces and major components of an aircraft. This vocabulary

should include: wing, fuselage, vertical and horizontal stabilizers, elevators, ailerons, rudder.6. Construct and test propellers and other devices for propelling a model aircraft.7. Describe differences in design between aircraft and spacecraft, and identify reasons for the design differences.

Properties of Airfill in blanks and

give examples

Air can be _________

Air has __________________

Air takes up ____________

Air exerts ____________

What is Air?

Air is primarily made up of two elements, nitrogen and oxygen. Nitrogen makes up 78.05% of air and oxygen another 20.95%. The remaining less than 1% is primarily argon, but carbon dioxide, neon, helium, methane and krypton are also present in air. Air also contains suspended dust, spores, and bacteria, as well as water.

How do we know that there is Oxygen in Air?

1. ______________

2. __________

3. ______________

Bernoulli’s Principle Daniel Bernoulli, in the 1700s, developed the principle that the speed of a fluid is directly related to pressure. That is, the faster the flow of a fluid, the lower the pressure that is exerted on the surface it is flowing over. For example, if air is flowing faster over the top of a surface than under a surface, the pressure on the top of the surface will be less than that underneath.

The air above the wing moves faster than the air below it. Slower air has higher pressure than faster air, so the air pressure pushing up on the bottom of the wing is greater than the pressure pushing down. When this happens the wing moves up and we have lift.

Bernoulli’s PrincipleExperiments

-describe how these experiments proved Bernoulli’s Principle

1.

2.

3.

Bird Flight

• Bird's wings are naturally thin with feathers creating a smooth surface.• Birds are different from airplanes in that they are able to get lift, thrust, and propulsion from

their wings.• When birds glide or soar their feathers allow them to maintain an optimum combination of lift

and drag forces.• A bird's skeletal system is designed so that it can easily fly through the air. The shoulder

joints are designed so that the inner wings are held at a proper angle to obtain the greatest lift.

• A bird's body is designed to be very aerodynamic helping to reduce drag.• Birds have feathers attached to a movable finger bone called the alula, found on the front of

each wing. The alula adjusts air flows aiding in lift.• By changing the shape of their wings and tail, birds can change the direction of their flight. • When landing birds will spread their feathers apart, lower their legs, and increase their angle of

approach to land safely. • Birds have well developed organs that aid in navigation.

Airplane Flight

• Airplanes are designed with thin wings and a smooth surface.• An airplane requires an engine and propellers to achieve lift and thrust. • Airplanes have adopted unique features such as winglets, slats and flaps to

stabilize the wings and improve lift. • A plane lowers the flaps on the trailing edge of the wing to achieve lift. • Attached to the wings are the inside flaps that make the airplane fly more slowly

and the outside ailerons that make the plane turn.• On an airplane there are slots that can be opened on the top of the wing to

increase the speed of air moving over the upper surface of the wing, increasing lift.

• A pilot is able to change the direction of an airplane by controlling the elevators and ailerons of an aircraft.

• When landing a plane a pilot uses wing flaps and slats to increase drag.• An aircraft has tails that work like a bird's, helping it to brake and steer.• An airplane pilot has instruments to help them navigate the airplane.

Aerodynamics (Streamlining)Airplanes and birds fly even though they are heavier than air. This amazing feat is the basis for the study of aerodynamics which examines the forces of lift, weight, thrust and drag. These forces affect every surface that moves through the air. A bird, for example, is aerodynamically designed. Its curved, feathered wings create lift, and the streamlined shape allows it to move through the air with little resistance. In the same way, aerodynamic engineers try to design airplanes whose shape will create maximum speed and lift, while minimizing the effects of drag.

Birds vs Airplanesmatch the plane’s parts to the birds

Forces of Flight Label the forces of flight and then match to their definitions

__________ is created by a plane's propeller or its jet engines.

__________ is the natural force of air that resists an airplane's forward movement.

___________ is created by the plane's wings as they move through the air.

___________ is the natural force that pushes a plane toward the ground.

Four basic forces are involved in the flight of an airplane: (1) ________.(2) ________. (3) ________.(4) ________.

Gravity and lift are opposing forces, as are drag and thrust. When the plane's lift equals the force of gravity and the force of thrust equals the drag, the plane remains in level, cruising flight. When one or more of these four forces change, the plane begins to change its altitude, direction, or speed.

Angle of AttackThe lift of the airfoil can be increased by tilting it upward at an angle to the air flow. This gives the airfoil a greater angle of attack

Air over smooth surface Air over rough surface

Drag

WeightLift

ThrustIf you have ever put your hand outside the window of a moving car, you have experienced drag. Your hand moving against the air causes two types of drag: pressure drag and skin friction drag. Pressure drag is created when a stream of air runs into an object and separates to get around that object. Skin friction drag is due to friction between air and the surface moving through it.

Drag and an Airplane's Design

To improve an airplane's performance designers consider the purpose and requirements of an airplane before thinking of form or structure. To reduce drag, they also consider how fast the airplane will be flying, the stickiness of the air (viscosity), and the "tug of war" relationship between drag and thrust. This is how we describe the battle between drag and thrust:

•If drag is greater than thrust, the airplane's speed decreases. •If drag is less than thrust, the airplane's speed increases. •If thrust and drag are equal, the airplane will fly

at a constant speed

Thrust is the force that propels or drives an airplane forward. This force can be produced by an engine spinning a propeller or a jet engine expelling hot gas from the back. In a propeller driven airplane, the blades are shaped like an airfoil. When the blades spin, they "cut" into the air pushing it backward, creating a difference in air pressure. This backward action on the air causes an equal reaction that propels the airplane forward. This forward motion is thrust.

In a jet engine airplane, thrust is a result of hot gases (exhaust) rushing out of the engine's nozzle. The action of the gases rapidly moving backward causes a reaction in the air. The air puts out a force equal to the thrust, but in the opposite direction, moving the airplane forward.

Flying a plane is challenging because of the "tug of war" between thrust and drag. A pilot must be aware of this relationship in order to maintain speed and control of an airplane's flight path. Here is what happens in the battle between thrust and drag: •If thrust is greater than drag, the airplane accelerates or

gains speed. •If thrust and drag are equal, the airplane continues to move

forward at a constant speed. •If drag is greater than thrust, the airplane decelerates or loses speed.

Just like your body, an airplane's weight is pulled downward toward Earth. To overcome and manage this downward pull, an airplane's initial design must be carefully considered.

The pilot is responsible for making sure the airplane's total weight is within the range it was designed to carry. He or she does this by making sure the total weight of the fuel, cargo, and passengers is within certain limits and is properly distributed. This keeps the plane balanced.

During flight, the pilot monitors lift closely because there is a "tug of war" battle between two forces: weight and lift. Weight pulls in one direction (down) while lift pulls in the other (up). Here is what happens in the battle between weight and lift:

•When weight (gravity) is greater than lift, the airplane sinks (descends).

•When lift is greater than weight, the airplane climbs (ascends).

•When the two forces are balanced, the airplane's flight path is steady and level.

Lift is produced by a pressure difference. Bernoulli proposed that changes in air speed are related to changes in air pressure. The slower the air moves, the greater the air pressure. Air pressure is the force air molecules exert on one another.

If we slice the wing of a typical commercial airplane and look at its cross-section, its shape looks like a stretched-out water droplet.This aerodynamic shape is referred to as an airfoil. Usually, the position of the airfoil in flight is set at an angle so that air first hits the wing's front edge and bottom. This causes the air stream to split. The air above the wing travels faster over a curved surface than the air below the wing. The faster air has a lower pressure than the slower air, and it is this pressure difference that generates lift.

Here is what happens in the battle between weight and lift: •When lift is greater than weight, the airplane climbs

(ascends). •When weight (gravity) is greater than lift, the airplane sinks

(descends). •When the two forces are balanced, the airplane's

flight path is steady and level.

Control Surfaces of a PlaneLabel and match the definitions

aileron•

elevator•

engine•

flap •

fuselage•

propeller•

rudder•

tail•

wing•

•twisted airfoil, or turning blade, powered by the engine and providing thrust

•retractable trailing edge of a wing that moves down to increase wing surface and

increase lift on takeoff

• surfaces on the outer edge of a wing that move up and down, controls side to side

motion

•body of an airplane, excluding the wing and tail section

•part of the aircraft that provides the power for takeoff, landing and sustains flight

•section of the plane housing the elevator, and rudder, also know as the vertical

stabilizer

•an airplane's airfoil, producing lift as the craft moves through the air. It has two

moveable controls: ailerons and flaps

•surface on the horizontal part of the tail section that moves up or down to assist

the aircraft in maintaining level flight and adjusting the pitch of the aircraft

•vertical part of the tail section that moves left or right to stabilize the aircraft,

controls the left and right motion

Control Surfaces of a PlaneWhat they do

An airplane in flight changes direction by movement of a system of flaps. The flaps deflect airflow and turn or tilt the airplane so that it rotates around the center of gravity, which lies between the wings. A pilot is capable of controlling flight direction by changing the pitch, roll, or yaw of an aircraft. Each action involves moving either the control column "stick" or the pedals, or both.

The ailerons are flap-like structures on the trailing edge of the wings -one on each side. When the pilot moves the control stick to the right, the right aileron will tilt up and the left aileron will tilt down. This will cause the airplane to roll to the right. When the pilot moves the control stick to the left, the left aileron tilts up, the right aileron tilts down and the airplane rolls to the left. This happens because as the aileron tilts downward more lift is created and the wing rises. As it tilts upward, less lift will be created and the wing will descend. If the wing on one side of the airplane rises and the other descends, the airplane will roll towards the side of the decrease in lift

Roll

The elevators are also flap-like structures that are mounted on each side of the horizontal stabilizer. When the pilot pushes the control stick forward, the elevators tilt downward. This causes the tail of the airplane to rise and the fuselage to tilt down - this is called pitching down. When the pilot pulls the control stick back, the elevators tilt upward, the tail goes down and the fuselage pitches nose-up. When the elevator tilts downward more lift is created (like the ailerons) and the tail rises. When the elevator tilts upward, less lift is created and the tail descends.

Pitch

The rudder is located on the fin. When the pilot pushes on the right rudder pedal, the rudder tilts to the right and the airplane yaws "nose-right." When the pilot pushes on the left rudder pedal, the rudder tilts to the left and the airplane yaws "nose-left." Remember that if the rudder is extended so that it obstructs the airflow, then the airflow is going to push hard on that rudder. This will cause the airplane to move away from the side where the rudder is extended. That is why when a pilot pushes the right rudder pedal, the rudder tilts to the right - the air will push harder on the right side of the tail causing the tail to swing left, which will cause the nose to swing right.

Yaw

Hot Air Balloon FlightLighter than air flight

Helicopter Flight

Identify and label the forces acting on a Hot Air

Balloon if flight.

How does a Hot Air Balloon create Lift? Thrust? explain

How does a helicopter fly?

A helicopter can take off and land vertically (straight up and down). It can fly in any direction, even sideways and backwards. It can also hover or hang in the air above a given place.

A helicopter gets its power from rotors or blades. When its rotors are spinning, a helicopter doesn't look much like an airplane. But the rotor blades have an airfoil shape like the wings of an airplane. So as the rotors turn, air flows more quickly over the tops of the blades than it does below. This creates enough lift for flight.

By changing the angle of attack of the propeller blade, the helicopter can fly in any direction

ParachutesExplain how a parachute works. What happens when the weight is greater than the lift, or Lift

os greater than weight?

Spacecraft - vs - AirplanesAircraft have different designs, depending on the purpose of that aircraft or the environment it flies in. For example, a jet is different in design and purpose than a helicopter - jets fly at high altitudes and high speeds, while helicopters have the ability to hover and manoeuver in close quarters.Spacecraft are unique, as they must operate in space and fly in a variety of environments. In actuality, space shuttles are hybrids of both an aircraft and spacecraft. There are many different types of spacecraft, depending on the purpose of the mission, destination and payload. The manned missions to the moon are examples of spacecraft designed for outer space, beyond Earth’s orbit. Identify the similarities and differences

between space and our atmosphere

Practice QuestionsAs your airplane speeds down the runway, you recall that lift occurs when the

A. force of drag is equal to the force of thrust B. force of gravity is greater than the force of thrust C. air above the wings is moving faster than the air below the wings D. air above the wings is moving at the same speed as the air below the wings

Jason notes that a hot-air balloon moves toward the ground when the

A. air inside the balloon is being heated B. weight of the balloon is greater than its lift C. air outside the balloon is heated by the sun’s

rays D. weight of the balloon is greater than its

drag

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2

3

Several seagulls are flying in the distance. Jason remembers that birds have thrust because they

A. have feathers B. flap their wings C. ride wind currents D. have hollow bones

The structures of a bird that have the same function as rudders on a plane are

A. curved wings B. pointed beaks C. strong muscles D. tail feathers

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5

Which of the following statements explains why the sponge did not get wet?

A. The air in the jar exerts pressure on the water.

B. The sponge is lighter than the air. C. The sponge does not absorb water. D. The air is more dense than the

sponge.

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You know that hot air balloons rise because

A. gravity is as strong as lift B. air currents carry the balloon up C. air inside the balloon is less dense than is air outside the balloon D. the fabric of the balloon is less dense than is cold air

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8

After takeoff, the pilot steadily increases the airplane’s speed and altitude. For this increase to occur,

A. thrust must equal drag and lift must equal gravity B. thrust must be greater than drag and lift must be greater than gravity C. thrust must equal drag and lift must be greater than gravity D. thrust must be greater than drag and lift must equal gravity

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The pilot explains that the airplane is like a bird in that both are streamlined in order to reduce

A. lift B. weight C. drag D. thrust

The pilot explains how the airflow around a wing produces the force that holds the airplane up. The airflow is fastest

A. behind the wing B. in front of the wing C. over top of the wing D. underneath the wing

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Jose explained that as the air moves into the bag, the volume of air in the bag will

A. keep increasing due to low air pressure in the ball B. start decreasing due to high air pressure in the ball C. stay the same because the air pressure in the ball and

bag is equal D. increase until the air pressure is equal in the ball and

the bag

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Peggy was designing a device to show how humans breathe. She knew that for her device to show how a human breathes, it would have to

A. use nitrogen and give off oxygen B. use carbon dioxide and give off oxygen C. use oxygen and give off nitrogen D. use oxygen and give off carbon dioxide

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