Lecture 4-Basic Aircraft

AVIATION HISTORYAVIATION HISTORY

Lecture 4: Basic Aircraft

By: Zuliana Ismail, 2010

Types of airplane and their usesCommercial airplane Scheduled and charter airline flights, carrying both

passengers and cargo. The larger passenger-carrying types are often referred

to as airliners Some of the smaller types are also used in general

aviation

Passenger/ Cargo Aircraft Airbus A380

Types of airplane and their uses

Military Fighters and bombers (shooting, combat) Search and rescue, reconnaissance (spying),

observation transport, and tanker aircraft among others.

Fighter Aircraft

Military airplane

Black WidowWorld’s Smallest Spy

Aircraft

Northrop B-2 Stealth Bomber

Refueling an airplane in mid-air

Types of airplane and their uses

General and Private General- Business jets , trainers, aerobatic

types, racers, gliders, firefighters, medical transports, and cargo transports.

Private- Light passenger, business, or recreational types.

Used for a wide range of commercial tasks, such as flight training, policing, crop spraying, and medical evacuations.

Private Aircraft

Crop Spraying

Medical Evacuations

Tiltrotor plane’s

Types of airplane and their uses

Experimental aircraft Built and used to explore some aspect of

aircraft design. The Bell X-1 rocket plane, which first broke

the sound barrier (travel more than speed of sound-supersonic) in level flight, is a famous example.

X-15

Major Parts of Airplane

WING

EMPENNAGE

ENGINE

FUSELAGE

Parts of an AirplaneFuselage: Basic structure of the airplane to which wings,

empennage and landing gear are attached. It is designed to hold passengers, crews & cargo.Empennage (tail): Consists of vertical stabilizer & horizontal

stabilizer. It provides the greatest stabilizing influence of all

the components of an airplane.

Parts of an Airplane

Engine: Provides the thrust necessary for powered flight. The types of engine depends on the mission

requirements of the airplane.Wing The wing is an airfoil attached to the fuselage and is

designed to produce lift. It may contain fuel cells, engine nacelles and landing

gear. Airplane control surfaces (aileron, flaps, slat and spoiler)

also attached on it.

Wing

High Wing: Wing on top (very stable)

Mid Wing: Wing in middle (acrobatic)

Low Wing: Wing on bottom (less drag)

Parts of an Airplane

Landing gear : The landing gear can be fixed in place or retractable. Many small airplanes have fixed landing gear which

increases drag, but keeps the airplane lightweight. Larger, faster and more complex aircraft have retractable

landing gear that can reduced weight. Most planes today use what is called a tricycle landing

gear arrangement. This system has two large main gear units located near

the middle of the plane and a single smaller nose gear unit near the nose of the aircraft.

Parts of an Airplane

Cockpit/ Flight Deck Front part of the fuselage and contains all the instruments

needed to fly the plane. The cockpits have hardened doors, securing them from

unauthorized persons during flight, takeoffs and landings. Cabin Section of the fuselage for passengers, cargo, or both. A

typical passenger cabin has galleys for food preparation; lavatories; one or more seating compartments & etc

Cargo Below the passenger deck where cargo and baggage are

carried.

Boeing 747

RudderAileronFlaps

ElevatorRudder

Primary Control Surfaces

Ailerons: horizontal surfaces located on wing tips. Provide roll control- Roll the aircraft to the

right or left. Elevator: horizontal surface located on the tail

Provide pitch control-Nosing the aircraft up and down.

Rudder: vertical surface located on the tail Provide yaw control- turning the aircraft to the

left or right.

Additional Control SurfacesFlaps: A movable control surface on the aircraft wing,

used to change the amount of lift generated. Flaps deflect downward during take-off & landing

to increase lift. Flaps retracted immediately after landing to

decrease lift.Slats: A movable control surface on the aircraft wing,

also used to change the amount of lift generated. Slats enable the airplane to get off the ground

quickly and to land more slowly.

Additional Control SurfacesSpoilers: Located on the upper wing which, when opened,

decreases lift and increases drag. They reduce lift by disrupting the airflow over the

top of the wing. They are used during the descend prior to landing

and immediately after landing.

Spoiler

Basic Aircraft

4 Forces acted on an 4 Forces acted on an airplaneairplane

4 Forces acted on airplane

1. Thrust The force that moves the aircraft through the

air. Generate by the engine

2. Lift This force is generated by the flow of air

around the airplane especially to the wing. Amount of lift generated depends on airspeed,

angle of attack, airfoil shape, wing area.

Lift Equation

ρ=density, V=velocity, S = wing area, Cl=coefficient of lift (vary wit h AoA).

In designing an aircraft wing, it is better to get the higher coefficient of lift.

Coefficient of lift is vary with angle of attack. That’s why by changing the angle of attack, the

amount of generated lift can be adjusted.

Forces acted on Aircraft3. Drag Drag is the force of resistance an aircraft ‘feels’ as it

moves through the air. Wing is designed to be smooth in order to reduce drag. Drag important during landing in order to slow down

the aircraft.4. Weight Weight is the earth’s gravity pulls down on objects and

gives them weight. It includes the aircraft itself, the payload and the fuel.

Airplane can fly because…….Airplane can fly because…….1. Four forces acted on the plane2. Thrust generated by the engine3. Lift force produced by airflow to the Wing.

4. Drag is air resistance 5. Weight is gravitational pull

ThrustThrustLiftLiftBoeing 747

How airplane flies? There are actually four forces (thrust, lift, drag

and weight) acting on airplane. When taking off, the plane is moving at high

speed on the runway due to the thrust generated by the engine.

As engines are attached to the wing of an airplane, its thrust will be applied to the airplane.

The airflows pass over the wings generate a lift force.

To allow the airplane take-off, Lift force must greater than the plane’s weight and thrust force must greater than the drag force .

How Lift is Created As airplanes speed up or move forward, air is

moving to the wings. Due to the shape of the airfoil which is the top

surface more curve than the below, makes the airflow travel faster over the top of the wing and slower below the wing. Lift

Slower Airflow

Faster Airflow

How airplane flies?

According to the Bernoulli’s principles ,an increase in velocity leads to a decrease in pressure.

So that, the air pressure below the wing is higher meanwhile the air pressure above the wing is lower.

This difference in pressure pushes the wings up. And as both wings are attached on the fuselage, the

whole airplane body also goes up. If enough lift is created or lift is greater than the

plane’s weight, the plane naturally lift into the air.

Airfoil SectionAirfoil is the cross section of the wing that produces lift or

any aerodynamic effect as it passes through the air. Leading Edge: Front edge of wing Trailing Edge: Back edge of wing Camber: Center line between top and bottom of wing Chord Line: Line connecting leading edge and trailing

edge

Angle of Attack (AoA) Relative wind: direction of the airstream in

relation to airfoil.

Angle of Attack (AoA): Angle between the chord line and the relative wind

Angle of Attack (AoA)

The angle of attack (AoA) is related to the amount of lift.

AoA , Lift It changes during a flight as the pilot changes

the direction of the airplane. Too high an AoA (exceed the critical value)

can cause the airplane stalls. Stall means airplane loss of LIFT force, thus

the airplane may goes down.

Stall: Loss of lift caused by the breakdown of airflow over the wing the Angle of Attack (AoA) passes a critical point.

Airplane Stability and Control

Airplane can be controlled by their three axes, roll axis, pitch axis and yaw axis. As an airplane moves through the air, their three axes system also moves.

This movement can be described by the movement of its center of gravity.

3 Main Control Surfaces The main control surfaces for an airplane are

the ailerons (for roll), elevators(for pitch) and rudder(for yaw).

Pilot control the movement of the airplane using the control sticks/ yokes and rudder pedals inside the cockpit.

control yokes

Ailerons Ailerons are used to roll or rotate the aircraft When the pilot moves the control stick to the

right the right aileron moves up and the left aileron moves down.

This causes more lift on the left wing and less lift on the right wing.

The difference in forces causes the aircraft to roll to the right.

Ailerons

When the pilot moves the control stick to the left the left aileron moves up and the right aileron moves down.

This causes more lift on the right wing and less lift on the left wing.

The difference in forces causes the aircraft to roll to the left.

Elevator

Elevators are used to pitch the aircraft up or down causing it to climb or dive

To climb, the pilot pulls the control stick back causing the elevators to deflected up.

This in turn causes the airflow to force the tail down and the nose up.

To dive, the pilot pushes the control stick forward causing elevator to deflect down.

This in turn causes the airflow to lift the tail up and nose down.

Rudder

The rudder turns the aircraft right or left. On the vertical tail, the rudder moves from side

to side, pushing the tail in a left or right direction. To turn right, the pilot steps on the right rudder

pedals. This causes rudder tilt to the right . When rudder tilts to the right , more lift is

created on the right, which pushes the vertical stabilizer to the left.

This in turn causes the airplane nose turn right.

Aircraft Engines

1903- 1940s: Propeller + Piston Engines Era

From 1903 (Wright bros.) until the Early 1940s, all aircraft used the piston engine combined with propeller as their propulsion system. Piston engine is just similar

with car engine except with several different.

A propeller is essentially a type of fan which transmits power by converting rotational motion into thrust to propel the aircraft (move forward).

Piston engine uses the energy produced by

burning a mixture of air and fuel to drive the

propeller.

Piper PA-28 Cherokee

Piston engineDifferent configurations of piston engines

The differences between piston aircraft engines and car engines Crankshaft – The crankshaft in an piston aircraft engine

turns a propeller, crankshaft in car engine is used to move the wheels of the car.

Weight – the piston aircraft engine must be lightweight compare to car engine.

Power demand to run the engines- the piston aircraft engine demands high power for very long times compare to car engines

Numbers of engine parts - an aircraft engine has at least two sets for every parts, including ignition system (spark plugs and magnetos) and fuel pumps compare to car engine that only have one set.

Operating environment different- an aircraft engine no need radiator for air-cooling compare to the car.

Propeller + PistonEngine Aircraft

Very efficient for low speed flight. Lower load capacity compared to similar sized jet

powered aircraft. Consumes less fuel, thus cheaper and much more

economic than jets. Quiet, but fly at lower speeds. The best option for people who need to transport a

few passengers and/or small amounts of cargo. Best choice for pilots who wish to own their own

aircraft. Propellers are not used on high speed aircraft.

Jet Engine History

1931: 1st turbojet engine designed 1930 by Sir Frank Whittle

1939: The 1st jet aircraft (Heinkel He 178) was developed in England and Germany

1943: The first jet fighter aircraft, Messerschmitt Me 262 went into service in the German Luftwaffe.

History of Aircraft Propulsion

1944 (After World War 2)-Today : Airplanes used jet engines to generate thrust. Jet engines also referred to as Gas Turbine

Engines. Various types (turbo-jet, turbo-prop, turbo-shaft,

turbo-fan , ramjet, scramjet) Messerschmitt Me-262 : 1st operational jet-powered

aircraft German V-1 bomb (pulse jet engine): 1st application

for military purposes. Bell P-59: 1st American aircraft MiG-15: 1st Soviet jet aircraft.

Jet Engines

Jet aircraft make use of turbines for the creation of thrust.

Consumes more fuel but provide much more thrust than a piston engine.

Fly faster than propeller driven aircraft. Greater weight capacity Example: Airbus A340 and Boeing 777, can carry

hundreds of passengers and several tons of cargo, and are able to travel for distances up to 13 thousand kilometers.

Noisy, this makes jet aircraft a source of noise pollution.

Newton's 3rd law

The theory of jet propulsion is based on the Newton’s third Law, which state that For every action there is an equal and opposite reaction.

When the jet engine is operating, it draws a lot of air from the front and after air-fuel burns the gas ejects at high speed.

During this process, the engine applies force to the gas and lets the gas accelerate in the backward direction and in the meantime, the gas also gives the engine a reactive force to push the aircraft to move forward.

Turbo-jet Engine

Inlet- inlet is the opening at the front of engine, it allows the outside air to enter the engine.

Compressor – compressor is made up of fans with many blades, it compress the air and raises the pressure & temperature of the air, the compressed air then is delivered to the burner.

Burner – Burning process occur here. Fuel is sprayed to the compressed air .The mixture of the fuel + air will be burned. The results is heated gas with high energy, high pressure and high temperature.

Turbine- turbine used some of the heated gas energy to turn the compressor . This energy is transferred through the shaft.

Nozzle- The balance of heated gas energy exits through the nozzle at very high speed. This causes thrust. As the jets of gas shoot backward, the engine and the aircraft are thrust forward.

(Newton 3rd Law)

Thrust

Newton's 3rd law: For every action there is an equal and opposite reaction. This is called thrust.

Turbo-prop Engine

•The propeller located at the front of engine •The propeller converts the power developed by the engine into thrust as efficiently as possible under all operating conditions.•These aircraft are popular with regional airlines, as they tend to be more economical on shorter journeys.

Hercules-1 C130

Turbo-fan Engine

Similar to the turboprop, except a fan replaces the turboprop propeller.

Larger fan at the front provides thrust in the same way as a propeller.

The turbofan engine has a front fan, which runs at the same speed as the compressor and fan turbine located at the back to drive the fan.

Most modern airliners use turbofan engines because of they can produce high thrust, lower fuel consumption and low engine-noise.

Rocket EngineRocket Engine A rocket engine produces thrust by burning a

fuel at high pressure and exhausting the gas through a nozzle.

The oxygen for combustion is carried with the propulsion system.

High temperatures and pressures is built up, the are used to accelerate the exhaust gases through a rocket nozzle to produce thrust.

The heavier the rocket , the greater thrust needed to get it off the ground.

Newton 3rd Law: “To every action there is an equal and opposite reaction."

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Differences between Jet engine and Rocket engine

Thrust direction Jet engine is an engine using jet propulsion

for forward thrust . Rocket engine is an engine using jet propulsion

for upward thrust.

Source of oxygen Jet engines do not have their own source of

oxygen. Outside air is sucked into the engine to act as an oxidizer

There is no air in space. Rockets have their own oxygen source, either a liquid tank, or mixed in with the solid fuel for combustion.

Rocket vs Missile

Purpose Rocket mission is to send the

satellite to outer space. Missile mission is as a weapon to

attack high value target. Guidance

Rocket no guidance system. Missile has a guidance system.