The Airplane
Lesson 1.1
Sep 2012
Reference
From the Ground Up
Chapter 1: The Airplane
Pages 3 - 14
Outline
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Airplane and Parts
Construction Materials and Stresses
Loads and Load Factors
Logbooks and Inspection
Aircraft Classes and Categories
The Airplane
• Aircraft - Any machine capable of flight
• Canadian Air Regulations (CARs) definition of an
Airplane:
– “Power-driven heavier-than-air aircraft deriving its lift in flight
from aerodynamic reactions on surfaces that remain fixed
under given conditions of flight."
• Some Airplane Classifications:
– Wing position (high/low/mid wing)
– Number of engines (single or multi-engine)
– Undercarriage (wheels, skis, floats, retractable and nonretractable)
Parts of an Airplane
• Essential components of airplane:
1. Fuselage (body)
2. Lifting Surfaces (wings)
3. Empennage (tail section)
4. Propulsion System (engines)
5. Undercarriage (landing gear)
• Airframe
– Complete structure of airplane, except for instruments and
engines
Parts of an Airplane
Empennage
Lifting Surface
Fuselage
Propulsion System
Undercarriage
Parts of an Airplane
Vertical Stabilizer
Rudder
Aileron
Flaps
Horizontal Stabilizer
Elevators
Wing Strut
Aileron
Propeller
Engine Cowl
Landing Gear
The Fuselage
• Central body of airplane
• Accommodates crew, passengers, and cargo
• Wings, tail, landing gear, and engine all attached to
fuselage
• Classed according to construction method (truss,
monocoque, semi-monocoque)
Truss
• Steel tubes (Longerons and Girders) form frame
• Principle member = Longerons (lengthwise tubes)
• Covered by fabric, metal or composite materials
• Frame takes all load
Truss
Longerons
Girders
Monocoque
• Solid structure (or skin) with no internal frame
(example: pop can)
• Usually made of composite materials
• Skin takes all load
Semi-Monocoque
• Monocoque structure with internal frame/stiffeners (Formers and
Stringers), covered with Stressed Skin.
• Principle Member = Formers (AKA Bulkheads)
• Formers and Stressed Skin take load
Semi-Monocoque
Formers
Stringers
Stressed Skin
The Wing
• Airplane wings either:
– Monoplanes - One pair of wings, most modern aircraft
– Biplanes - Two pairs of wings, older designs
The Wing
• Wing shapes:
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Rectangular
Tapered (from wing root to wing tip)
Elliptical
Delta
The Wing
• Wings attached:
– Bottom of fuselage = low wing
– Middle of fuselage = mid wing
– Top of fuselage = high wing
The Wing
• High wings either:
– Externally braced (supported by struts)
– Fully cantilevered (no struts)
Inside The Wing
• Spars run from wing root to wing tip
– One spar = monospar
– More than one = multispar
• Ribs run from leading edge to trailing edge
– They are cambered (curved) to give wing shape
– Wing covering attached to ribs
• Compression Struts hold spars in place and take
some of the load between them
The Wing
Spar
Compression
Strut
Rib
Parts of the Wing
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Ailerons
– Control surfaces near wing tips on trailing edge
– Allow airplane to Roll
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Wing Root = Section of wing closest to fuselage
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Wing Tip = Outer edge of the wing, farthest from fuselage
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Chord
– Imaginary line between leading and trailing edge of wing
– Mean Aerodynamic Chord (MAC) is average of chord along wing (if wing
tapers)
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Span = Maximum distance from wing tip to wing tip
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Flaps
– Attached to trailing edge of wing, close to fuselage
– They increase or decrease camber of that section of wing
The Tail (Empennage)
• Four main parts:
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Vertical Stabilizer (AKA Fin)
Rudder
Horizontal Stabilizer (AKA Stabilizer)
Elevator
• Horizontal stabilizer is airfoil which balances aircraft, and
provides longitudinal stability
• Vertical stabilizer is vertical surface which provides directional
stability
• Elevator
– Control surface for pitch (up and down motion of airplane)
– Hinged to horizontal stabilizer, provides longitudinal control
The Tail (Empennage)
• Rudder
– Control surface for yaw (left and right motion of plane)
– Hinged to vertical stabilizer, provides directional control
• Stabilator
– Horizontal stabilizer and elevator combined into one surface.
– Pivots around point where it’s hinged onto fuselage
• Trim tab
– Surface fixed or hinged onto control surface
– Helps pilot by taking pressure off flight controls during various
phases of flight
• Canard
– Horizontal Stabilizer and lifting surface on nose of aircraft
The Propulsion System
• Planes powered by:
– Piston-engines (props)
– Turbine engines (turbo-props)
– Jet engines (jets)
• Most small airplanes in use today have piston engines
similar to car engines
The Landing Gear
• Landing gear:
– Supports aircraft on surface
– Takes shock of landing
• Landing Gear can be either:
– Nose Wheel (AKA tricycle)
– Tail Wheel (AKA tail-dragger)
• Landing gear can also be fixed or retractable
(reduces drag)
Control Systems
• Three main control surfaces
– Rudder (controls yaw)
– Elevator (controls pitch)
– Ailerons (controls roll)
• Rudder controlled by foot pedals
• Elevator and ailerons controlled by control column,
which can either be a control stick (or “stick”) or a
control wheel (or “yoke”). Some airplanes may also
have side-yokes or side-sticks.
Control Systems
Control
Wheel
Control Systems
Control
Stick
Trim
• Used by pilot to help take some pressure off flight controls
• Trim Tabs
– Hinged to trailing edge of ailerons, rudders and elevators
– May be fixed or controllable
• Some trimming methods:
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Trim Tabs
Anti-servo Tabs
Servo Tabs
Adjustable Stabilizer
Moveable Tail
Spring Trim
Electric Trim
Construction Materials
• Aircraft frames must be: light, strong and rigid (stiff)
• Some materials:
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Steel
Dural (aluminum alloy with copper and magnesium)
Alclad (dural between two layers of pure aluminum)
Magnesium Alloy
Honeycomb Sandwich Construction (metal
honeycomb pattern between two sheets of metal
– Composite (fiberglass cloth and epoxy resin molded
over a foam form)
– Wood
– Fabric
Corrosion
• Normally caused by oxidation, which is reaction
between metal and moisture in the air, causing
surface to dissolve (Example: Rust)
• Forms of corrosion are:
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Oxidation
Intercrystalline
Dissimilar Metals
Stress Corrosion
Corrosion Fatigue
Fretting Corrosion
Stresses
• Stress - Force that can cause a strain
• Strain - Distortion (changing of shape) of an object
due to stress
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5 types of stresses:
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Compression (crushing)
Tension (stretching)
Torsion (twisting)
Shearing (cutting)
Bending
Loads and Load Factors
• Wing Loading - Gross weight divided by area of lifting surfaces
(lb per sq ft)
• Span Loading - Gross weight divided by span (lb per ft)
• Power Loading – Gross weight divided by engine horsepower
(lb per hp)
• Load Factor - Ratio of live load (actual load on wings) to dead
load (Gross Weight, or aircraft weight on ground)
Logbooks
• Aircraft Journey Log
– Always carried on aircraft during flight
– Records daily flight time, air time, fuel and oil added, maintenance
etc
• Aircraft Technical Log
– Not carried on aircraft
– Records everything concerning maintenance, repairs and
modifications
• Personal Logbooks
– Logs every flight by pilot
– Records flight time, airplane, routes etc
– Also records licences, training info and total flight time
Logbooks
• Air Time - Starts when wheels leave ground, ends
when wheels touch back down
• Flight Time - Starts when aircraft starts moving under
its own power to when it stops, for the purpose of
flight
Inspection
• Pilots must inspect aircraft before each flight, for
general airworthiness, fuel and oil etc
• All aircraft must be periodically inspected by a
qualified maintenance engineer and certified as
airworthy in the aircraft technical and journey logs
Common Licence Types
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Student Pilot Permit
Recreational Pilot Permit
Glider Pilot Licence
Private Pilot Licence
Commercial Pilot Licence
Airline Transport Pilot Licence
• Class and type ratings can
be added to above licences
Aircraft Classes
• Categories
– General definitions of aircraft
– Examples: Airplanes, rotorcraft, gliders, lighter-than-air, powered-lift
• Classes
– Categories are split into classes
– Examples: Single-engine, multi-engine, landplane, seaplane,
helicopter, gyroplane, balloon etc
• Types
– Specific models of aircraft
– Examples: Cessna 172, Boeing 747, Schweitzer 2-33
Next Lesson
2.1 - Theory of Flight
The Four Forces
From the Ground Up
Chapter 2.1.1:
Forces Acting on an Airplane in Flight
Pages 15 - 20