Transcript AER 101 Introduction to Aeronautics Instructor : Prof. Dr

AER 101 Introduction to Aeronautics
Instructor : Prof. Dr. Galal Bahgat Salem
Textbook : John D. Anderson, Jr,
Introduction to Flight , 4th Edition ,
2000 .
Term Work : 25 +25 = 50 Marks
Final Exam: 50 +50 = 100 Marks
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
AER 101 A Introduction to Aeronautics ( 2 + 1 )
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History of Flight
Nature of Aerodynamic Forces
Airplane components and Configurations
Scope of Aeronautical Engineering
Fluid Properties and Characteristics
Atmosphere
Basic Aerodynamics : Kinematics, Continuity and
Bernoulli’s Equations, Boundary Layer Concept, Skin
Friction, Pressure Drag, Flow Separation, Streamlining
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
AER 101B Introduction to Aeronautics ( 2 + 1 )
• Geometric and Aerodynamic Characteristics of Airfoils
• Dimensional Analysis and Aerodynamic Force
Coefficients
• Elements of Airplane Performance: Drag-Speed Curve,
Cruising Flight Performance, Climbing Performance,
Gliding Performance
• Elements of Propulsion: Propellers, Piston Engines,
Reaction Principle, Jet Engines, Rocket Motors
• Elements of Airplane Stability and Control
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
Chapter 1
History Of Flight
What is Flight ?
■ Flight is a motion in air free from ground
topography
■ It is a high-speed motion through a lowresistance ( low density ) medium which is air
N.B. Compare flight in air, having a density of
1.225 Kg/m3, with shipping in water of density
1000 Kg/m3
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
Short History of Flight
1. Imitating Birds
• People attempting to fly by using artificial wings
strapped to their arms and-or legs
• The flapping of wings generate lift
• The Greek myth of Daedalus and his son Icarus
imprisoned on the island of Crete in the
Mediterranean Sea illustrates man’s flight
• The idea of strapping a pair of wings to arms fell
out of favor
• It was replaced by concept of wings flapped up
and down by various mechanical devices,
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
Powered by human arm, leg, or body movement
• These are called Ornithopters
• Ornithopters first designed by Leonardo da
Vinci ( 1452-1519 )
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
Leonardo da Vinci
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
Why Don’t Ornithopters Work?
• G. A. Borelli (1680 ) realized the fact that (
power/weight) ratio of a man is much less
than that of bird
• Hence man will never be able to fly like a
bird, by his own power only
2. Lighter-than-Air Balloons[Unpowered Flight]
● Firstly hot air balloons discovered by the
Montgolfier Brothers in France (1783)
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
• Later on gas balloons of Hydrogen/Helium were
used by Charles
• Charles found that ballooning is based on
Archimedes principle of buoyancy
• Unmanned Balloon
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Manned Balloon
Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
3. Lighter-than-Air Dirigibles (Airships)[Powered]
●Firstly invented by Count von Zeppelin in
Germany (1900)
●They are more rigid (the first airframe) than
balloons, controlled and directed (using
stabilizing surfaces) and propeller droved
●Large bags of gas inside the rigid airframe
●Count von Zeppelin (1929), flew around the world
in 21 days
●Hydrogen fired in “Hindenburg” dirigible in 1937
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
4.Sir George Cayley (1799)
●First pioneered the concept for the modern airplane
configuration in 1799
- Fixed wings, tail, fuselage
- Separate mechanism for propulsion
“separation of lift and propulsion”
● Recognized that the function of thrust was to overcome
aerodynamic drag
●Drew the first lift-drag vector diagram in the history
N.B. Before this time flapping wings were supposed to
provide both lift and propulsion
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
Lift
Thrust
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Resultant Aerodynamic
Force
Drag
Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
5.Heavier-than-Air Unpowered Gliders (Sailplanes)
• Gliders first designed and flew by Otto Lilienthal,
a German mechanical engineer, in 1891
• Lilienthal is known as the glider’s man
• Gliders characterized by un-sustained flight
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
He died in 1896, after stalling a glider he was flying
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
6.Heavier-than-Air Powered Airplanes
• Samuel P. Langley was contracted to build a flying
machine for the U.S. government
• Began a series of aerodynamic experiments in 1887
• Successful in flying several small scale, unmanned,
powered aircraft, which he called aerodromes
• These were the first steam-powered, heavier-than-air
machines to successfully fly
• Langley’s attempt to build a manned aerodrome failed
• Lunched and crashed on Oct. 7 and December 8, 1903
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
Langley’s aerodrome shortly after launch
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
• The Wright Brothers
• Wright brothers (Orville&Wilbur) were the
inventors of the first practical manned flight on
17 Dec.,1903 (Flyer I )
• It was a strut-and-wire biplane configuration
• Propulsion was achieved by a four-cylinder inline engine designed and built by Orville Wright
• It produced close to 12 hp and weighed 140 Ibs
• It drove two propellers via a bicycle-like chain
loop
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
• The control feature of Wright flyer is one of the basic
reasons for its success
• Flyer I had a wing span of 12 m , flew a distance of 256
m, and lasting 59 sec
Wright Flyer Engine
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
Wright Flyer engine
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
■ Hydrostatics of Lighter-than-Air Flight
• The lifting force is the buoyancy force
• The basic laws of hydrostatics (fluid at rest) are:
a- fluid pressure p is uniform in horizontal
planes, as well as the density
b- p varies only with height z according to the
Hydrostatic equation
z
datum
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
dp/dz = -ρg
Integrating, in case of constant density:
p + ρ g z = constant
This is the hydrostatic equation
p
non-uniform
p distribution
on a body immersed
in a fluid at rest
z
B
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p+ρ g z
Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
• The resultant fluid-pressure force is called the
buoyancy force B, acting vertically upward, and
equals to the weight of the displaced fluid
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B=ρgV
where ρ density of fluid
g acceleration of gravity
V volume of immersed body
N.B. The basis of Heavier-than-air Flight will
discussed later
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
Anatomy OF THE AIRPLANE
■The Main Components of the Airplane
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
• The basic airplane components include:
fuselage, wing, tail assembly, control surfaces,
landing gear, and power plant(s)
1.The Fuselage
♦ It carries the payload.
♦ It is the central structural member of the
airframe to which other members are attached.
♦ It is generally streamlined to reduce drag.
♦ Designs vary with the mission to be performed,
as illustrated in figure
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
2.The Wing
● It generates the lift force.
• It includes the flaps for lift augmentation during
landing and takeoff, and ailerons for banking
the airplane during turning.
• The wing cross-section is called Airfoil
• The airfoil shape, wing planform shape, and
placement of the wing on the fuselage depend
upon the airplane mission.
• The figure illustrates wing shapes and
placements
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
3.Tail Assembly and Control Surfaces
• The tail assembly (empennage) represents the
collection of structures at the rear of the airplane
• The tail assembly consists of:
1- The vertical stabilizer (fin) and rudder which
provide directional stability in yaw
2-The horizontal stabilizer and elevator which
provide longitudinal stability in pitch
● The figure illustrates different forms of tail
assembly
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
4.Landing Gear
• The landing gear (undercarriage) supports the
airplane while it is at rest on the ground and
during the takeoff and landing
• The gear may be fixed or retractable
• The wheels are attached to shock-absorbing
struts that use oil or air to cushion the blow of
landing
• Special types of landing gear include skids for
snow and floats for water
• For carrier landings, arrester hooks are used
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
4.Power Plants
• Power plants used to produce the thrust force
necessary to propel the airplane to overcome
the drag
• The power plant consists of the engine (and
propeller, if present) and accessories
• The main engine types are:
-Reciprocating (or piston type)
-Reaction engines such as turbojet, turbofan,
turboprop, ram jet, pulse jet, and rocket engine
The figure shows several some of engine
placements
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
■The Aircraft Structure
• The figure shows a cutaway drawing of an
aircraft structure
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
Basic Elements of Aircraft Structure
■The wing
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
• Wing structure basically same in all aircraft
types
• Modern aircrafts have all metal and composite
material wings but many older had wood and
fabric wings
• The wing is a framework composed of spars,
ribs and (possibly) stringers (see figure)
• Spars are the main members of the wing. They
extended lengthwise of the wing (crosswise of
fuselage)
• Most wing structures have two spars, the front
spar and the rear spar
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
• Front spar near the leading edge, while
the rear spar at about two-thirds the
distance to the trailing edge
• The ribs are the parts of the wing which
support the covering and provide the airfoil
shape
• A skin covers the wing framework
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
■The Fuselage
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
• The fuselage structural elements are:
1-Bulkheads, which form the cross-sectional
shape of the fuselage
2-Longerons, which are heavy strips that run
the length of the fuselage and are attached to
the outer edge of the bulkheads
3-Fuselage skin, which is attached to the
longerons
N.B. Keelson is a strong beam placed at the
bottom of the fuselage. The keelson is frequently
used in military fighter aircrafts
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
■ Aerodynamic Basis of Heavier-than-Air Flight
• This is the real flight
• It needs a lifting force to balance the weight;
since the buoyancy force is not sufficient
• The source of the lifting force is the fact that
when a fluid is in motion, its pressure varies not
only with height, as in the case of rest, but also
with its velocity
• The relation between p, V, and z is expressed by
Bernoulli’ equation (1738) :
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
p + (1/2) ρ V2 + ρ gz = constant
• Where
p
static pressure
dynamic pressure
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(1/2) ρ V2
ρgz
head pressure
•
• The shape of an airplane-wing cross section
(known as aerofoil or airfoil) was evolved from
the Venturi tube, as shown :
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
• When a fluid flows over a body (or a surface), or
when a body is forced to move through a fluid,
the fluid velocity relative to the body surface may
be increased or decreased (depending on
surface shape and altitude)
• And consequently the fluid pressure p may
decrease or increase according to Bernoulli’s
equation
• The resultant will be a net fluid force F acting
on the body which is completely different than
the Buoyancy force (and may be many times
greater than it)
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
How does an Airplane fly?
• The key to the generation of lift is the speciallydesigned streamlined body, called the wing,
and characterized by a special cross-section,
called airfoil
• When the wing is propelled through air at a
suitable angle of attack, and with a relativelyhigh speed, the air flowing around its surface is
accelerated and/or decelerated according to
Bernoulli’s equation
• The integration of the air-pressure distribution
over the surface of the wing results in a resultant
aerodynamic force F
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
• The component of R perpendicular to flight
direction (direction of relative motion) is called
the Lift L
• The component of R opposite to flight direction
is called drag D
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
Forces on an Airplane
Basically, the four forces acting on an airplane are
weight, thrust, lift, and drag
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
• Weight: The weight includes the airplane itself,
the payload, and the fuel. Since the fuel is
consumed as the airplane flies, the weight
decreases. Weight acts in a direction towards
the center of the Earth.
• Thrust: The driving force of whatever propulsive
system is used, engine driven propeller, jet
engine, rocket engine, and so forth, is the thrust.
It may be taken to act along the longitudinal axis
of the airplane.
• Lift: This force is generated by the flow of air
around the airplane, the major portion resulting
from the wing. It represents the component of
the resultant aerodynamic force normal to the
flight direction. Prof. Galal Bahgat Salem
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Aerospace Dept., Cairo
• Drag: This force arises from the flow of air
around the airplane and is the component of the
resultant aerodynamic force opposite to the flight
direction
• For un-accelerated (Steady) level flight:
L=W
T=D
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
Scope of Aerospace Engineering
• Aerospace engineering means airplane, missiles
(Rockets), and satellite design, manufacturing,
testing, maintaining, repairing, overhauling, and
performance analysis
▄ The Main Topics A.E. are:
(1) Aerodynamics
(2) Airframe Design
(3) Propulsion
(4) Flight Mechanics & Control
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
■ The Associated Topics are:
►Flight navigation
►Electronics ( + Flight navigation = Avionics )
►Meteorology
►Metallurgy
►Production Engineering
►Fluid-power engineering (pneumatic,
hydraulic, pressurization, and air-conditioning
systems)
►Instrumentation
►Chemical & fuel engineering
►Flight regulations & Airworthiness
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
■ The Associated Topics are:
►Flight navigation
►Electronics ( + Flight navigation = Avionics )
►Meteorology
►Metallurgy
►Production Engineering
►Fluid-power engineering (pneumatic,
hydraulic, pressurization, and air-conditioning
systems)
►Instrumentation
►Chemical & fuel engineering
►Flight regulations & Airworthiness
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
Aerodynamics
●Aerodynamic design of the flight vehicle/space
vehicle for:
►Maximum lift production
►Minimum drag
►Max. available space for structure and payload
●Determination of the aerodynamic forces on the
designed configuration at the different flight
conditions (speed, attitude, and a altitude)
● Wind-tunnel testing
●Flight testing
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
Propulsion
●Power-plant design & construction for:
►Max. thrust/weight of engine
►Max. thrust/drag of engine
►Min. specific fuel consumption (sfc)
►Good performance at different altitudes and
speeds of flight
●Power-plant manufacturing
●Power-plant testing
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
Airframe Design
●Structural analysis
●Airframe design & construction for: sufficient
strength and with less weight
●Airframe manufacturing techniques
●Airframe testing techniques
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo
Flight Mechanics & Control
●Stabilizing and control surfaces design
●Control surfaces operation and
performance
●Aircraft stability analysis
●Maneuverability considerations
●Airplane systems and instrumentation
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Prof. Galal Bahgat Salem
Aerospace Dept., Cairo