Theory of Flight
6.01 Aircraft Design and Construction
References:
FTGU pages 9-14, 27
Main Teaching Points
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Parts of an Airplane
Aircraft Construction
Landing Gear
Standard Terminology
Definition
The airplane is defined as:
• A power-driven…
• Heavier-than air aircraft…
• Deriving its lift in flight from aerodynamic
reactions…
• On surfaces that remain fixed under given
conditions of flight.
Parts of an Airplane
Parts of an Airplane
Parts of an Airplane
Parts of an Airplane
Fuselage
The fuselage is the main body of the aircraft, where the
passengers, cargo and crew go.
Fuselage
• The fuselage is normally classified according to the type
of construction:
• -Truss Type
• -Monocoque
• -Semi-monocoque
Fuselage – Truss Type
Fuselage – Semi-Monocoque
Empennage
• The empennage is the rear portion of the airplane
• It is integral to control and stability during flight
Wing Construction
• Spars
 spanwise members
 wood or metal
 carry bending loads
• Ribs
 web or truss
 give wing its
cambered shape
Wing Construction
 Edges
 Leading Edge
 Trailing Edge
 Strength & Shape
 Wires
 Internal / External
 Bracing for strength
 Covering
 Metal or Fabric
 Metal  strength
Wing Layouts
• High Wing
• Mid Wing
• Low Wing
• Bi-Plane
Wing Layouts
• High Wing
• Mid Wing
• Low Wing
• Bi-Plane
Wing Layouts
• High Wing
• Mid Wing
• Low Wing
• Bi-Plane
Wing Layouts
• High Wing
• Mid Wing
• Low Wing
• Bi-Plane
Confirmation
Landing Gear
• Conventional (Tail-Dragger) - Two main wheels
and a tail wheel
• Tricycle – Two main wheels and a nose wheel
• Retractable - Wheels may be raised so that they
are enclosed in wings or fuselage (reducing
drag)
• Fixed - Landing gear is not designed to retract
Landing Gear
Landing Gear
Landing Gear
Landing Gear
Landing Gear
Retractable Landing Gear
• PROS
• Reduced drag at cruise
• Higher cruising speed
• CONS
• Added weight
• Added mechanical complexity
• Risk of “Gear Up” Landing (land based)
• Risk of “Gear Down” Landing (amphibious)
Landing Gear
Shock Absorption
• Absorb the impact of landing, or the effect of bumps in runway.
• Spring steel Landing Gear
• Air/Oil oleos
• Rubber cords (bungee) or discs
• Low pressure tires
Landing Gear
Main Landing Gear
- Spring Steel Cantilever -
Landing Gear
Nose Landing Gear
- Air / Oil Oleo -
Landing Gear - Brakes
Brakes
• Provide a means of stopping the aircraft
• Assist with steering on the ground
Confirmation
• How would you
describe the aircraft to
the left?
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-tail dragger?
-tricycle gear?
-retractable gear?
-float plane?
-high wing?
-low wing?
-mid wing?
-biplane?
• Request the use of the
tools to label the
aircraft.
Wing Span
• Wingspan is the maximum distance from wing tip to wing tip
Chord
Chord is the imaginary line
between the leading edge and
the trailing edge of the wing
• A measure of the width of a wing
Wing Area
Wing Area
• Length of the wing multiplied by the average width of wing
Planform
Planform
• Shape of the wing as
seen from above
Aspect Ratio
Aspect Ratio
• Ratio of the span to chord of the wing
• A measure of how SLENDER the wing is
Airfoil
• A structure curved to produce lift
Camber
Camber
• A measure of the curvature
of an airfoil
• Mean Camber is the line
equidistant between the
upper & lower surfaces
Angle of Incidence
Angle of Incidence
• Angle between chord line and the longitudinal axis
Relative Airflow
Relative Airflow
• Airflow over the wing
• Related to the forward motion of the aircraft through the
air
Angle of Attack
Angle of Attack
• The angle between the chord line and the relative airflow
• It is a measure of how much the wing ‘bites’ into the air
Confirmation
Confirmation Check
Confirmation
What kind of landing gear is this?
Confirmation
What is the angle of attack?
Confirmation
What are some of the differences between
powered aircraft and gliders?
Confirmation
• Reading: From the Ground Up, pages 914
• The next Theory of Flight Class covers the
basic flight controls (6.02)