Federal Aviation Administration

Federal AviationAdministration

1NORTH FLORIDA REGION

OCTOBER 02, 2010BASIC AERODYNAMICS

Federal AviationAdministrationBASIC

AERODYNAMICS PART I

PRESENTED BY: Dennis H. WhitleyFAASTeam Lead Representative

NORTH FLORIDA REGION




SHOW ME A PILOT THAT CAN’T ANSWER A

CORRELATIVE QUESTION AND/OR CAN’T PERFORM A GIVEN TASK, & I’LL SHOW

YOU A PILOT THAT DOESN’T UNDERSTAND

WHAT HE/SHE IS TRYING TO ACCOMPLISH.

MY MOTTO




FLIGHT INSTRUCTING MUST NOT BE THE BY-

PRODUCT OF BUILDING FLIGHT

HOURS.




BUILDING FLIGHT HOURS MUST BE THE BY-PRODUCT

OF FLIGHT INSTRUCTING.




SAFETYCOMMITMENT

VSDEDICATION


6NORTH FLORIDA FSDO-15JANUARY 27, 2010

AERODYNAMICSPART I

THIS DISCUSSION IS BASED ONSUBSONIC AIRCRAFT AND WILL BE

“VERY BASIC”“NO FORMULAS”

“VERY LITTLE MATH”




WE WILL TALK ABOUTATMOSPHERIC PRESSURE

4 FORCES LIFT/WEIGHT/THRUST/DRAGGROUND EFFECT

TURNING TENDENCIESTRIM DEVICES

AERODYNAMICS OF SPINSSLIPS/SKIDS

ADVERSE YAW




WHAT IS ATMOSPHERIC PRESSURE?

ATMOSPHERIC PRESSURE IS THE WEIGHT OF ALL THE AIR UPON THE

SURFACE OF THE EARTH.




WHAT DOES 30 hg MEANS?HOW WAS ATMOSPHERIC

PRESSURE MEASURED?

MER CURYCON TAINERWITHMER CURY

GL ASS TUBE 1 SQU ARE INCH INNER DIA METER BY 35 IN CHES TALLRULE RTORIC ELLI'S MEAS UREMEN T

MER CURYCON TAINERWITHMER CURY

GL ASS TUBE 1 SQU ARE INCH INNER DIA METER BY 35 IN CHES TALLRULE RTORIC ELLI'S MEAS UREMEN T

M ERCURYCO NTAINERW ITHM ERCURY

GLASS TUBE 1 SQUARE INCH INNER DIAMETER BY 35 INCHES TALL

RULER

TORICELLI'S MEASUREMENT

36

YARD STICK

36 INCHES TALL

MERCURIALBAROMETER

TORICELLI'SRULER

36YARD STICK

MERCURIALBAROMETER

TORICELLI'SRULER

36YARD STICK

SEA LEVEL

ATMOSPHERIC PRESSURE

30.00MERCURIALBAROMETER

TORICELLI'S

MERCURY

HOW WAS THE DROP OF PRESSURE

WITH ALTITUDE VERIFIED?




HOW WAS THE WEIGHT OF THE

AIR DETERMINED?

M E R C U R Y

14.7 lbs. 14.7 lbs.

1 SQUARE INCH

29.92" hg.




WHATIS AN ALTIMETER?

A PRESSURE DIFFERENTIAL GAUGE

FROMSOURCE

HG0

5

40

10

35

3025

2015

HG0

5

40

10

35

3025

2015

HG0

5

40

10

35

3025

2015

FROMSOURCE

StaticPort

KollsmanWindow

SEA LEVEL

static portpressure31.00 hg.

sealevel

pressure31.00 hg.

31.0031.00

sealevel

pressure31.00 hg.

static portpressure23.00 hg.

31.0031.00

WHAT IS ALTIMETER SETTING?

SEA LEVEL PRESSURE CORRECTED FOR NONSTANDARD TEMPERATURE.




WHAT IS THE MAIN REASON THAT AN AIRPLANE IS ABLE

TO FLY?BECAUSE OF THE WEIGHT

OF THE AIR.In other words the

aerodynamic effect air has on the aircraft.




The branch of science that deals with the forces produced by air flowing over specially shaped surfaces called airfoils.

DEFINITION OF AERODYNAMICS




IS THERE ANY THING WRONG WITH THIS PICTURE?

TWO THINGSTHE FLOWING OF THE RELATIVE WIND

THE DIRECTION OF THE RELATIVE WIND

CAN WE FLY WITH A FLAT WING?




AT CRUISE COSTANT ALTITUDE

1ST LAW: Every object in a state of uniform motion tends to

remain in that state of motion unless an external force is applied to it. 3RD LAW:

For every action there is an equal and opposite reaction.







MINIMUM MANEUVERING SPEEDMINIMUM MANEUVERING SPEEDSLOW FLIGHTSLOW FLIGHT




STALLSTALL

PA-28 SERIES




WHAT IS THE DEFINITION OF FOIL?

TO PREVENT FROM BEING SUCCESSFUL TO THWART

AIRFOIL•Any surface designed to deflect the airflow passing over it or striking it, and thereby obtaining an useful reaction

AN AIRFOIL IS ANAIR DEFLECTOR




HOW MANY AIRFOILS ARE

THERE?




•AIRPLANE WING.•AILERONS.

•SLATS•LANDING FLAPS.

•VERTICAL STABILIZER.•RUDDER.

•HORIZONTAL STABILIZER.•ELEVATOR/STABILATOR

•TRIM TABS.•PROPELLER.

•ROTOR BLADE.

•FUSELAGE.FUSELAGE.•FEARING.FEARING.•STRUTS.STRUTS.




WHAT IS LIFT?




A FORCE CREATED BYA FORCE CREATED BYA DEFLECTION OF AIRA DEFLECTION OF AIR

AND PRESSURE DIFFERENTIAL AROUND AN AND PRESSURE DIFFERENTIAL AROUND AN AIRFOIL.AIRFOIL.

IS CALLED LIFT WHEN IT ACTS UPWARD.IS CALLED LIFT WHEN IT ACTS UPWARD. WHEN IT ACTS DOWNWARD IS CALLED WHEN IT ACTS DOWNWARD IS CALLED

NEGATIVE LIFT. NEGATIVE LIFT. WHEN IT ACTS SIDEWAYS IS CALLED SIDE WHEN IT ACTS SIDEWAYS IS CALLED SIDE

LIFT.LIFT.WHEN IT ACTS FORWARD IS CALLED THRUSTWHEN IT ACTS FORWARD IS CALLED THRUST




HOW IS LIFT CREATED?

DEFLECTION -- ISSAC NEWTON

AIR’S CHANGE OF DIRECTION--BERNOULLI'S PRINCIPLEPRESSURE DIFERENTIAL-- BERNOULLI'S

PRINCIPLE

AIR PASSING BY AN AIRFOIL







WHAT’S WRONG WITH THIS PICTURE










CAN WE FLY WITHOUT THE HELP

OF BERNOULLIS?










THRUST•Thrust is a reaction force described

quantitatively by Newton's second and third laws. When a system expels or accelerates mass in one direction the

accelerated mass will cause a proportional but opposite force on that system.




LIFT•LIFT is a reaction force described

quantitatively by Newton's second and third laws. When a system expels or accelerates mass in one direction the

accelerated mass will cause a proportional but opposite force on that system.

•Thrust is LIFT DIRECTED FORWARD.




THE PROPELLER’S DEFLECTION OF AIRTHE PROPELLER’S DEFLECTION OF AIR










DRAG




PARASITE DRAG FORM

INTERFERENCE




GROUND EFFECTCOMMANDER TYSON

INDUCED DRAG




ASSUMEDASSUMEDANGLE ANGLE

OF ATTACKOF ATTACK

ASSUMED RELATIVE WINDASSUMED RELATIVE WIND

ASSUMED ASSUMED LIFTLIFT DOWNWASH

STAGNATION AREAUPWASH

RELATIVE WIND

IS THAT RIGHT?IS THAT RIGHT?




STAGNATION AREA

UPWASHDOWNWAS

HRELATIVE CURRENT




ASSUMED ASSUMED LIFTLIFT

INDUCED RELATIVE WINDINDUCED RELATIVE WIND

INDUCEDINDUCEDANGLE ANGLE

OF ATTACKOF ATTACKINDUCED INDUCED

LIFTLIFT






OF ATTACKOF ATTACK

DOWNWASDOWNWASHHASSUMED ASSUMED

LIFTLIFTINDUCED INDUCED

LIFTLIFT







OF ATTACKOF ATTACK

INDUCED INDUCED LIFTLIFT

DOWNWASDOWNWASHH

WING WING TIPTIPVORTICEVORTICESSTOTAL ENDUCED DRAGTOTAL ENDUCED DRAG

UPWASH MODIFIESUPWASH MODIFIESRELATIVE WINDRELATIVE WIND

DOWNWASH PULLSDOWNWASH PULLSBACK ON LIFT VECTORBACK ON LIFT VECTOR

WING TIP VORTICES PULLS LIFT VECTOR FURTHER BACKWING TIP VORTICES PULLS LIFT VECTOR FURTHER BACK

WINGWINGTHREE-DIMENSIONALTHREE-DIMENSIONAL

FLOWFLOW







OF ATTACKOF ATTACK


DOWNWASDOWNWASHH

WING WING TIPTIPVORTICEVORTICESSTOTAL ENDUCED DRAGTOTAL ENDUCED DRAG







OF ATTACKOF ATTACK


DOWNWASDOWNWASHH






OF ATTACKOF ATTACK






WASHOUT

WHAT DOES THE

STABILATOR DO?

WHAT DOES THE

ANTI-SERVO TAB DO?

A

B

C

STABILIZED UNACCELERATED CLIMB

IF DESCENDINGIN A 60 ° BANK

HOW MANY G ’S?




DYHEADRAL




ADVERSE YAW




OVERBANKING TENDENCIES




MANEUVERING SPEED VA




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