Post on 03-Jun-2018
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2Wednesday, July 30, 2014 Elements of Aeronautics
Elements of Aeronautics
Basics of basics
How to be happy in EOA?
Try to attend all the classes
Take notes on the class, maintain a notebook
Just read it every evening for 30 minutes
Own 2 books on Basics (Low Price Editions
available)
Do the Assignments and Cycle Tests properly...
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3. Introduction to Aerodynamics
Aerodynamic forces on aircraft
Classification of NACA Aerofoils, Aspect ratio, Wing
Loading, Mach NumberCentre of Pressure , Aerodynamic Centre
Aerofoil characteristics Life and Drag curves
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3.1. Aerodynamic Forces on Aircraft
The science of the action of air on an object, and with
the motion of air on other gases. Aerodynamics deals
with the production of lift by the aircraft, the relative
wind, and the atmosphere.
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3.1. Aerodynamic Forces on Aircraft
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Four forces on Aircraft
3.1. Aerodynamic Forces on Aircraft
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Thrust is the forward force produced by the power plant
/propeller. It opposes or overcomes the force of drag.
Drag is a rearward, retarding force, and is caused by disruption
of airflow by the wing, fuselage, and other protruding objects.
Weight is the combined load of the airplane itself, the crew, the
fuel, and the cargo or baggage. Weight pulls the airplane
downward because of the force of gravity.
Lift opposes the downward force of weight, is produced by the
dynamic effect of the air acting on the wing, and acts
perpendicular to the flight path through the wings center of lift.
Four forces on Aircraft
3.1. Aerodynamic Forces on Aircraft
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Reference axes system in Aircraft
3.1. Aerodynamic Forces on Aircraft
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Reference axes
3.1. Aerodynamic Forces on Aircraft
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Pitching moment
3.1. Aerodynamic Moments on Aircraft
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Rolling moment
3.1. Aerodynamic Moments on Aircraft
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Yawing moment
3.1. Aerodynamic Moments on Aircraft
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3.2. Geometric Parameter of Wing
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3.2. Geometric Parameter of Wing
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Mean Chamber Line:Set of points halfway between upper and lower surfaces
Measured perpendicular to mean chamber line itself
Leading Edge:Most forward point of mean chamber line
Trailing Edge:Most reward point of mean chamber line
Chord Line:Straight line connecting the leading and trailing edges
Chord, c:Distance along the chord line from leading to trailing edge
Chamber:Maximum distance between mean chamber line and chord line
Measured perpendicular to chord line
3.2. Geometric Parameter of Wing
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3.2. Geometric Parameter of Wing
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3.2. Geometric Parameter of Wing
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3.2. Geometric Parameter of Wing
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3.2. Geometric Parameter of Wing
3 2 eometr c Parameter
o W ng
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3.2. eometr c Parameter o W ng
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3.2. Geometric Parameter of Wing
Dihedral Angle: The positive acute angle between the lateral axis of
an airplane and a line through the center of a wing or horizontal
stabilizer. Dihedral contributes to the lateral stability of an airplane.
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3.3. Classification of NACA Aerofoil
First digitspecifies maximum camber in percentage of chord
Second digitindicates position of maximum camber in tenths of chord
Last two digitsprovide maximum thickness of airfoil in percentage of chord
Example: NACA 2415 Airfoil has maximum thickness of 15%
of chord (0.15c)
Camber of 2%(0.02c) located 40%
back from airfoil leading edge (0.4c)
NACA 2415
AOA 2
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AOA = 2
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AOA 3
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AOA = 3
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AOA 6
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AOA = 6
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AOA 9
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AOA = 9
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AOA 12
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AOA = 12
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AOA 20
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AOA = 20
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AOA 60
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AOA = 60
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AOA 90
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AOA = 90
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3.2. Geometric Parameter of Wing
Lift coefficient (or lift) linearvariation with angle of attack, a
Cambered airfoils have
positive lift when a = 0
Symmetric airfoils have
zero lift when a =0
At high enough angle of attack,
the performance of the airfoil
rapidly degrades stall
Cambered airfoil has
lift at a=0
At negative aairfoil
will have zero lift
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3.2. Geometric Parameter of Wing
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3.2. Geometric Parameter of Wing
3 2 Geometric Parameter of Wing
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3.2. Geometric Parameter of Wing
Pressure Distribution on Aerofoil
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3.2. Geometric Parameter of Wing
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3.2. Geometric Parameter of Wing
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3.2. Geometric Parameter of Wing
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3.2. Geometric Parameter of Wing
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3.2. Geometric Parameter of Wing
3 2 G i P f Wi
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3.2. Geometric Parameter of Wing
3 2 G i P f Wi
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3.2. Geometric Parameter of Wing
3 2 G i P f Wi
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3.2. Geometric Parameter of Wing
3 2 G t i P t f Wi
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3.2. Geometric Parameter of Wing