Aviation Fundamentals 1 - Flight

8/8/2019 Aviation Fundamentals 1 - Flight

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Aviation Fundamentals

Session 1How Do Airplanes Fly?


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Forces Acting on an Airplane in Flight

LIFT

WEIGHT

THRUSTDRAG


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What causes the forces acting on the

airplane?

Weight Gravity

Thrust EnginesLift Wings and body shapeDrag Resistance from air


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How does a wing produce lift?

Wing is moving through air in this direction


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Pressure DifferentialCaused by air moving faster over top of wing

P Total

P Total = P Static + P Dynamic

P Static TOP

P Dynamic BOTTOM

P Dynamic TOP

P Static BOTTOM

P Static TOP < P Static BOTTOM P Dynamic TOP > P Dynamic BOTTOM


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LiftCaused by net upward force

Pressure acting on a surface produces a force.


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Angle of Attack

Chord

Relative Wind


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Angle of Attack

Relative Wind


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DownwashForce is required to change the direction of the air


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LiftResultant opposite force on wing

Lift Force

Downwash Force


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Lift Equation

Lift = V2 CL

A

density of air

V velocity of airflow

CL

coefficient of lift

A area of object


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StallAngle of attack is so large that wing stops producing sufficient lift

A stall can be induced atany airspeed, depending on theeffective weight of the airplane.


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Effective WeightBanking requires added g force, increasing effective weight.

Lift to support airplane basic weight

Lift to support

airplane effective weight


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Washout

1 > 2

2

1

Wing root stalls before wingtip


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Wing DihedralAdds stability in roll


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Lift Differential


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Sideslip Effect

1 2

1 > 2Therefore, additional lift is produced on the lower wing,

and the airplane tends to right itself.


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Changing Lift

Lift = V2 CL

A


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Changing Lift

Lift = V2 CL

A


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Changing Lift

Lift = V2 CL

A

Change Change wingprofile

Wing Flap


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Changing Lift

Lift = V2 CL

A

Change wingarea

Wing Flap


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Basic Flight ControlsChange airplane attitude by changing lift

Rudder

Ailerons

Elevators

Flaps


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Rudder

Yaw


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Ailerons

Roll


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Elevators

Pitch


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Drag

Power is required to force the airplane through the air.


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Drag Equation

Drag = V2 CD A

density of air

V velocity of airflow

CL

coefficient of drag

A area of object


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Sources of Drag

Parasite Drag

(Friction)


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Lift Force

Drag Force

Induced Drag(Drag due to Lift)


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Wave Drag

E N E R G Y E N E R G Y E N E R G Y E N E R G Y


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Reducing Wave Drag

Fineness

(Length/Width)

Greater curvature creates greater speed increase


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Airflow Airflow

Chord 1 Chord 2

Chord 2 > Chord 1

Wing 2 finer than Wing 1

Speed increases less over Wing 2

Airflow producing lift

BUT Lift is less

1 2


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Area Rule

Baseline Body Profile

Cross-section area must follow baseline body profile


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Area

Length


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Area

Length


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Pressure 2Pressure 1

Pressure 1 > Pressure 2

Base Drag

Net backward force (drag)


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Reducing Base Drag

P 1

P1 = P2

P1 > P2

P 2

P1P2


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Drag Curves


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Power Curves


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SpoilersOn large airplanes, used to modify lift and drag


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Aid in Descent

Drag


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Aid in Stopping

Drag

Weight on Wheels


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Questions?

Aviation Fundamentals 1 - Flight

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