the airplane

Sep 2012Lesson 1.1

The Airplane

Reference

From the Ground UpChapter 1: The AirplanePages 3 - 14

Outline• 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 non-

retractable)

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

Fuselage

Lifting Surface

Propulsion System Undercarriage

Parts of an Airplane

Propeller

Landing Gear

Wing Strut

Aileron

Flaps

Vertical Stabilizer

Horizontal Stabilizer

Rudder

Elevators

Engine Cowl

Aileron

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

Stressed SkinStringersFormers

The Wing • Airplane wings either:

– Monoplanes - One pair of wings, most modern aircraft

– Biplanes - Two pairs of wings, older designs

The Wing• Wing shapes:

– 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

Rib

CompressionStrut

Spar

Parts of the Wing• Ailerons

– Control surfaces near wing tips on trailing edge– Allow airplane to Roll

• Wing Root = Section of wing closest to fuselage

• Wing Tip = Outer edge of the wing, farthest from fuselage

• Chord– Imaginary line between leading and trailing edge of wing– Mean Aerodynamic Chord (MAC) is average of chord along wing (if wing

tapers)

• Span = Maximum distance from wing tip to wing tip

• 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:

– 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:– 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:– 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:– 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

• 5 types of stresses:– 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• Student Pilot Permit• Recreational Pilot Permit• Glider Pilot Licence• Private Pilot Licence• Commercial Pilot Licence• Airline Transport Pilot Licence

• Class and type ratings canbe 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 FlightThe Four Forces

From the Ground UpChapter 2.1.1:Forces Acting on an Airplane in FlightPages 15 - 20