Principles of Flight-Principles of Flight-AerodynamicsAerodynamics

Sean HowardSean Howard

KY Dept. of AviationKY Dept. of Aviation

What makes and airplane fly?What makes and airplane fly?

Ingredients for FlightIngredients for Flight

Bernoulli’s PrincipleBernoulli’s Principle Newton’s Laws of MotionNewton’s Laws of Motion InertiaInertia EnergyEnergy Velocity and AccelerationVelocity and Acceleration Three Dimensional MovementThree Dimensional Movement Stability and ControllabilityStability and Controllability

Atmospheric PropertiesAtmospheric Properties

The atmosphere is a fluid and exhibits fluidThe atmosphere is a fluid and exhibits fluid

properties. properties.

Many of the principles of fluid dynamics applyMany of the principles of fluid dynamics apply

to the atmosphere.to the atmosphere.Bernoulli’s principleBernoulli’s principleNon-CompressibilityNon-Compressibility

Parts of an AirplaneParts of an Airplane

CockpitCockpit Fuselage-”Spindle Fuselage-”Spindle

Shaped”Shaped” WingWing FlapFlap Aileron-”Little Wing”Aileron-”Little Wing”

Empennage-”Feather Empennage-”Feather the Arrow” the Arrow”

StabilizersStabilizers RudderRudder ElevatorElevator EngineEngine

Activity

Four Forces of FlightFour Forces of Flight

LiftLift

Lift is an aerodynamic forceLift is an aerodynamic force Lift must exceed weight for flightLift must exceed weight for flight Generated by motion of aircraft through airGenerated by motion of aircraft through air Created by the effects of airflow past wingCreated by the effects of airflow past wing Aircraft lift acts through a single point called Aircraft lift acts through a single point called

the the center of pressurecenter of pressure..

Two Possible ExplanationsTwo Possible Explanations

Bernoulli’s PrincipleBernoulli’s Principle

Newton’s Third LawNewton’s Third Law

• http://www.grc.nasa.gov/WWW/K-12/airplane/bernnew.html

• Aviation institute Teacher’s Guide-Anderson & Eberhardt, The Newtonian Description of Lift

Bernoulli’s PrincipalBernoulli’s Principal

Pressure Drop in Venturi Tube

Bernoulli Every DayBernoulli Every Day

Garden Hose (Thumb or Nozzle)Garden Hose (Thumb or Nozzle) Perfume atomizerPerfume atomizer Chimney on a windy dayChimney on a windy day Tornados often blow windows Tornados often blow windows outout PumpsPumps CarburetorsCarburetors

Bernoulli’s StripBernoulli’s StripActivity

Bernoulli DemonstrationBernoulli Demonstration

Newton’s Third LawNewton’s Third Law

For every action there is an equal andFor every action there is an equal and

opposite reaction.opposite reaction.

Newtonian DescriptionNewtonian DescriptionThe The actionaction is the turning of the air. The is the turning of the air. The reactionreaction is an upward is an upward

force (Lift).force (Lift).

DownwashDownwashThe air that is forced downward after it is turned creates

downwash.

So now what!So now what!

The air flowing across a wing is turned and The air flowing across a wing is turned and deflected downward due to the shape of the deflected downward due to the shape of the wing. Applying Newton’s third law, an equal wing. Applying Newton’s third law, an equal and opposite force to the downwash is and opposite force to the downwash is applied upward. This upward force is called applied upward. This upward force is called LiftLift..

See “The Newtonian Description of Lift”, Anderson & EberhartSee “The Newtonian Description of Lift”, Anderson & Eberhart

Factors that Affect LiftFactors that Affect Lift

Lift Equation: L=CLift Equation: L=CLL*.5r*A*V*.5r*A*V22

CCL L is a function of is a function of AOAAOA

R is air R is air densitydensity A is A is wing areawing area V is velocity or V is velocity or speedspeed

NASA FoilSimENASA FoilSimE

ActivityActivity

Teacher Institute DVDTeacher Institute DVD

Use the Foilsim to show factors that affect lift.Use the Foilsim to show factors that affect lift.

Complete Characteristics of Wing & Lift AreaComplete Characteristics of Wing & Lift Area

Worksheet (NASA).Worksheet (NASA).

Inventing FlightInventing Flight

Video ClipVideo Clip

Unit 2 Introduction; Wings That WorkUnit 2 Introduction; Wings That Work

WeightWeight

Weight is not constantWeight is not constant Varies with passengers, cargo, fuel loadVaries with passengers, cargo, fuel load Decreases as fuel is consumed or payload off-Decreases as fuel is consumed or payload off-

loadedloaded

Direction is constant toward earth’s centerDirection is constant toward earth’s center Acts through a single point called the center Acts through a single point called the center

of gravity (the CG)of gravity (the CG)

ThrustThrust

Forward-acting force opposes dragForward-acting force opposes drag Direction of thrust depends on designDirection of thrust depends on design Propulsion systems produce thrustPropulsion systems produce thrust Equal to drag in straight, constant speed Equal to drag in straight, constant speed

flightflight

Balloon on a StringBalloon on a String

ActivityActivity

Demonstrates Newton’s Third Law and thrust.Demonstrates Newton’s Third Law and thrust.

CAP-Module 4, Page 11CAP-Module 4, Page 11

DragDrag

An aerodynamic forceAn aerodynamic force Resists forward motionResists forward motion Increases with the square of speedIncreases with the square of speed Two broad drag classificationsTwo broad drag classifications

– Parasite dragParasite drag: drag created by airplane shape: drag created by airplane shape

A result of air viscosity.A result of air viscosity.– Induced dragInduced drag: by-product of lift generation: by-product of lift generation

Caused by the wingtip vortices.Caused by the wingtip vortices.

Wingtip Vortex

Energy is lost during the formation of the vortex.

This energy loss is Induced Drag.

Wingtip VorticesWingtip Vortices

A parachute is a real Drag!A parachute is a real Drag!

ActivityActivity

What type of drag is exhibited by a What type of drag is exhibited by a parachute?parachute?

Parachutes on a 747Parachutes on a 747

Parafoils

Planes and ParachutesPlanes and ParachutesCirrus only one certifiedCirrus only one certified

Lets Build and Airplane!!Lets Build and Airplane!!

ActivityActivity

Assemble the Sky Streak included with theAssemble the Sky Streak included with the

Inventing Flight module.Inventing Flight module.

Inventing Flight DVD: Unit 2, Lesson 2-4aInventing Flight DVD: Unit 2, Lesson 2-4a

Pre-FlightPre-Flight

EnergyEnergy

Potential-Energy that is stored as a resultPotential-Energy that is stored as a result

of position.of position.

Kinetic-Energy in motion.Kinetic-Energy in motion.

Inventing Flight Teacher GuideInventing Flight Teacher Guide

Page 79Page 79

What makes an airplane turn?What makes an airplane turn?

Newton’s First LawNewton’s First Law

An object at rest tends to An object at rest tends to stay at reststay at rest and andan object in motion tends to an object in motion tends to stay instay inmotionmotion with the same speed and in the with the same speed and in thesame direction unless acted upon by ansame direction unless acted upon by anoutside force. outside force. The tendency of and object to resist aThe tendency of and object to resist achange in motion is change in motion is InertiaInertia..

Based on Newton’s First Law: For Based on Newton’s First Law: For an object to travel in a circular an object to travel in a circular

path, a force must be exerted on path, a force must be exerted on the object to turn it.the object to turn it.

What is this force called?What is this force called?

Centripetal Force!Centripetal Force!

Ball on StringBall on String

Horizontal Component of Lift

The Invisible String

Three Axes of MovementThree Axes of Movement

If I were an AirplaneIf I were an Airplane

ActivityActivity

Stand up and move your body in threeStand up and move your body in three

dimensions.dimensions.

Three AxesThree Axes

ActivityActivity

Soda Straw DemonstratorSoda Straw Demonstrator

CAP-Module 1, Page 17CAP-Module 1, Page 17

StabilityStability

Two TypesTwo Types Static-The initial movement of an object Static-The initial movement of an object

after being disturbed.after being disturbed.

Dynamic-The behavior of the object over Dynamic-The behavior of the object over time.time.

StabilityStability

Positive-Neutral-Negative

Salad Bowl and BallSalad Bowl and Ball

ActivityActivity

Demonstrate stability with clear bowl and ballDemonstrate stability with clear bowl and ball

bearing.bearing.

Stabilized by DesignStabilized by Design

Empennage (Longitudinal & Vertical)Empennage (Longitudinal & Vertical) Dihedral (Lateral)Dihedral (Lateral) Anhedral (Lateral)Anhedral (Lateral) Incidence (Lateral)Incidence (Lateral) Yaw damper (Vertical)Yaw damper (Vertical) Keel Effect (Vertical & Lateral)Keel Effect (Vertical & Lateral)

Take a Breath!!!Take a Breath!!!

I hope you enjoyed basic aerodynamics!I hope you enjoyed basic aerodynamics!