BASIC AERODYNAMICS PART I

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BASIC AERODYNAMICS PART I
PRESENTED BY Dennis H. Whitley FAASTeam Lead
Representative NORTH FLORIDA REGION
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MY MOTTO
SHOW ME A PILOT THAT CANT ANSWER A CORRELATIVE
QUESTION AND/OR CANT PERFORM A GIVEN TASK,
ILL SHOW YOU A PILOT THAT DOESNT UNDERSTAND
WHAT HE/SHE IS TRYING TO ACCOMPLISH.
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FLIGHT INSTRUCTING MUST NOT BE THE BY-PRODUCT
OF BUILDING FLIGHT HOURS.
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BUILDING FLIGHT HOURS MUST BE THE BY-PRODUCT OF
FLIGHT INSTRUCTING.
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SAFETY COMMITMENT VS DEDICATION
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THIS DISCUSSION IS BASED ON SUBSONIC AIRCRAFT AND
WILL BE

• VERY BASIC
• NO FORMULAS
• VERY LITTLE MATH

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WE WILL TALK ABOUT
ATMOSPHERIC PRESSURE 4 FORCES LIFT/WEIGHT/THRUST/D
RAG GROUND EFFECT TURNING TENDENCIES TRIM
DEVICES AERODYNAMICS OF SPINS SLIPS/SKIDS ADVERSE
YAW
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WHAT IS ATMOSPHERIC PRESSURE?
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ATMOSPHERIC PRESSURE IS THE WEIGHT OF ALL THE AIR
UPON THE SURFACE OF THE EARTH.
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WHAT DOES 30 hg MEANS?
HOW WAS ATMOSPHERIC PRESSURE MEASURED?
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HOW WAS THE DROP OF PRESSURE WITH ALTITUDE
VERIFIED?
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HOW WAS THE WEIGHT OF THE AIR DETERMINED?
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WHAT IS AN ALTIMETER?
A PRESSURE DIFFERENTIAL GAUGE
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FROM SOURCE
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Static Port
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static port pressure 31.00 hg.
sea level pressure 31.00 hg.
31.00
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static port pressure 23.00 hg.
sea level pressure 31.00 hg.
31.00
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WHAT IS ALTIMETER SETTING?
SEA LEVEL PRESSURE CORRECTED FOR NONSTANDARD
TEMPERATURE.
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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.
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DEFINITION OF AERODYNAMICS
The branch of science that deals with the forces
produced by air flowing over specially shaped
surfaces called airfoils.
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IS THERE ANY THING WRONG WITH THIS PICTURE?
TWO THINGS
THE FLOWING OF THE RELATIVE WIND
THE DIRECTION OF THE RELATIVE WIND
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CAN WE FLY WITH A FLAT WING?
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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
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MINIMUM MANEUVERING SPEED SLOW FLIGHT
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STALL
PA-28 SERIES
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WHAT IS THE DEFINITION OF FOIL? TO PREVENT FROM
BEING SUCCESSFUL TO THWART
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AIRFOIL

• 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
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HOW MANY AIRFOILS ARE THERE?
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• AIRPLANE WING.
• AILERONS.
• SLATS
• LANDING FLAPS.
• VERTICAL STABILIZER.
• RUDDER.
• HORIZONTAL STABILIZER.
• ELEVATOR/STABILATOR
• TRIM TABS.
• PROPELLER.
• ROTOR BLADE.

• FUSELAGE.
• FEARING.
• STRUTS.

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WHAT IS LIFT?
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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
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HOW IS LIFT CREATED?
AIR PASSING BY AN AIRFOIL
DEFLECTION -- ISSAC NEWTON
AIRS CHANGE OF DIRECTION--BERNOULLI'S PRINCIPLE
PRESSURE DIFERENTIAL-- BERNOULLI'S PRINCIPLE
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WHATS WRONG WITH THIS PICTURE
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CAN WE FLY WITHOUT THE HELP OF BERNOULLIS?
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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.

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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.

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THE PROPELLERS DEFLECTION OF AIR
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DRAG
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PARASITE DRAG
FORM INTERFERENCE
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INDUCED DRAG
GROUND EFFECT
COMMANDER TYSON
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STAGNATION AREA
UPWASH
RELATIVE WIND
ASSUMED LIFT
ASSUMED ANGLE OF ATTACK
DOWNWASH
ASSUMED RELATIVE WIND
IS THAT RIGHT?
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STAGNATION AREA
UPWASH
DOWNWASH
RELATIVE CURRENT
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ASSUMED LIFT
INDUCED ANGLE OF ATTACK
INDUCED LIFT
INDUCED RELATIVE WIND
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DOWNWASH
ASSUMED LIFT
INDUCED ANGLE OF ATTACK
INDUCED LIFT
INDUCED RELATIVE WIND
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DOWNWASH
ASSUMED LIFT
INDUCED ANGLE OF ATTACK
WING TIP VORTICES
INDUCED LIFT
TOTAL ENDUCED DRAG
INDUCED RELATIVE WIND
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WING THREE-DIMENSIONAL FLOW
UPWASH MODIFIES RELATIVE WIND
DOWNWASH PULLS BACK ON LIFT VECTOR
WING TIP VORTICES PULLS LIFT VECTOR FURTHER BACK
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DOWNWASH
ASSUMED LIFT
INDUCED ANGLE OF ATTACK
INDUCED LIFT
INDUCED RELATIVE WIND
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ASSUMED LIFT
INDUCED ANGLE OF ATTACK
INDUCED LIFT
INDUCED RELATIVE WIND
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ASSUMED LIFT
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WASHOUT
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WHAT DOES THE STABILATOR DO?
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WHAT DOES THE ANTI-SERVO TAB DO?
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STABILIZED UNACCELERATED CLIMB
A
B
C
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IF DESCENDING IN A 60 BANK HOW MANY G S?
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DYHEADRAL
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ADVERSE YAW
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OVERBANKING TENDENCIES
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MANEUVERING SPEED VA
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LOAD FACTOR