BASIC AERODYNAMICS PART I Federal Aviation Administration PRESENTED BY: Dennis H. Whitley FAASTeam Lead Representative NORTH FLORIDA REGION

MY MOTTO 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.

FLIGHT INSTRUCTING MUST NOT BE THE BY-PRODUCT OF BUILDING FLIGHT HOURS.

BUILDING FLIGHT HOURS MUST BE THE BY-PRODUCT OF FLIGHT INSTRUCTING.

SAFETY COMMITMENT VS DEDICATION

THIS DISCUSSION IS BASED ON SUBSONIC AIRCRAFT AND WILL BE “VERY BASIC” “NO FORMULAS” “VERY LITTLE MATH”

4 FORCES LIFT/WEIGHT/THRUST/DRAG WE WILL TALK ABOUT ATMOSPHERIC PRESSURE 4 FORCES LIFT/WEIGHT/THRUST/DRAG GROUND EFFECT TURNING TENDENCIES TRIM DEVICES AERODYNAMICS OF SPINS SLIPS/SKIDS ADVERSE YAW

WHAT IS ATMOSPHERIC PRESSURE?

ATMOSPHERIC PRESSURE IS THE WEIGHT OF ALL THE AIR UPON THE SURFACE OF THE EARTH.

HOW WAS ATMOSPHERIC PRESSURE MEASURED? WHAT DOES 30 hg MEANS? HOW WAS ATMOSPHERIC PRESSURE MEASURED?

36 YARD STICK 36 INCHES TALL

36 YARD STICK

36 YARD STICK

HOW WAS THE DROP OF PRESSURE WITH ALTITUDE VERIFIED?

HOW WAS THE WEIGHT OF THE AIR DETERMINED?

A PRESSURE DIFFERENTIAL GAUGE WHAT IS AN ALTIMETER? A PRESSURE DIFFERENTIAL GAUGE

HG 5 40 10 35 30 25 20 15 HG 5 40 10 35 30 25 20 15 FROM SOURCE FROM SOURCE HG 5 40 10 35 30 25 20 15

Kollsman Window Static Port

static port pressure 31.00 hg. sea level pressure 31.00 hg.

static port pressure 23.00 hg. sea level pressure 31.00 hg.

SEA LEVEL PRESSURE CORRECTED FOR NONSTANDARD TEMPERATURE. WHAT IS ALTIMETER SETTING? SEA LEVEL PRESSURE CORRECTED FOR NONSTANDARD TEMPERATURE. 25

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.

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

IS THERE ANY THING WRONG WITH THIS PICTURE? TWO THINGS THE FLOWING OF THE RELATIVE WIND THE DIRECTION OF THE RELATIVE WIND

CAN WE FLY WITH A FLAT WING?

3RD LAW: For every action there is an equal and opposite reaction. 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. AT CRUISE COSTANT ALTITUDE

MINIMUM MANEUVERING SPEED SLOW FLIGHT

STALL PA-28 SERIES

WHAT IS THE DEFINITION OF FOIL? TO PREVENT FROM BEING SUCCESSFUL TO THWART

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

HOW MANY AIRFOILS ARE THERE?

HORIZONTAL STABILIZER. AIRPLANE WING. AILERONS. SLATS LANDING FLAPS. VERTICAL STABILIZER. RUDDER. HORIZONTAL STABILIZER. ELEVATOR/STABILATOR TRIM TABS. PROPELLER. ROTOR BLADE. FUSELAGE. FEARING. STRUTS.

WHAT IS LIFT?

A FORCE CREATED BY A DEFLECTION OF AIR AND PRESSURE DIFFERENTIAL AROUND AN AIRFOIL. IS CALLED LIFT WHEN IT ACTS UPWARD. WHEN IT ACTS DOWNWARD IS CALLED NEGATIVE LIFT. WHEN IT ACTS SIDEWAYS IS CALLED SIDE LIFT. WHEN IT ACTS FORWARD IS CALLED THRUST

HOW IS LIFT CREATED? AIR PASSING BY AN AIRFOIL DEFLECTION -- ISSAC NEWTON AIR’S CHANGE OF DIRECTION--BERNOULLI'S PRINCIPLE PRESSURE DIFERENTIAL-- BERNOULLI'S PRINCIPLE

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.

Thrust is LIFT DIRECTED FORWARD. 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 AIR

DRAG

PARASITE DRAG FORM INTERFERENCE

INDUCED DRAG GROUND EFFECT COMMANDER TYSON

STAGNATION AREA UPWASH RELATIVE WIND DOWNWASH ASSUMED LIFT ASSUMED ANGLE OF ATTACK DOWNWASH ASSUMED RELATIVE WIND IS THAT RIGHT?

STAGNATION AREA UPWASH RELATIVE CURRENT DOWNWASH

ASSUMED LIFT INDUCED ANGLE OF ATTACK INDUCED LIFT INDUCED RELATIVE WIND

DOWNWASH ASSUMED LIFT INDUCED ANGLE OF ATTACK INDUCED LIFT INDUCED RELATIVE WIND

DOWNWASH ASSUMED LIFT INDUCED ANGLE OF ATTACK WING TIP VORTICES INDUCED LIFT TOTAL ENDUCED DRAG INDUCED RELATIVE WIND

WING THREE-DIMENSIONAL FLOW UPWASH MODIFIES RELATIVE WIND DOWNWASH PULLS BACK ON LIFT VECTOR WING TIP VORTICES PULLS LIFT VECTOR FURTHER BACK

DOWNWASH ASSUMED LIFT WING TIP VORTICES TOTAL ENDUCED DRAG INDUCED ANGLE OF ATTACK INDUCED LIFT INDUCED RELATIVE WIND

DOWNWASH ASSUMED LIFT INDUCED ANGLE OF ATTACK INDUCED LIFT INDUCED RELATIVE WIND

ASSUMED LIFT INDUCED ANGLE OF ATTACK LIFT INDUCED RELATIVE WIND

WASHOUT

WHAT DOES THE STABILATOR DO?

WHAT DOES THE ANTI-SERVO TAB DO?

STABILIZED UNACCELERATED CLIMB

IF DESCENDING IN A 60 ° BANK HOW MANY G ’S?

DYHEADRAL

ADVERSE YAW

OVERBANKING TENDENCIES

MANEUVERING SPEED VA

LOAD FACTOR