Lecture 3: Basic Aircraft AVIATION HISTORY Lecture 3: Basic Aircraft

Types of Airplane Commercial Military General/Private Experimental

Types of airplane and their uses Commercial 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: Detecting & attacking enemy targets Air to air missiles/guns Air to ground: Bombs, Missiles Supplying weapons to other aircraft Transport: Soldiers, VIP/VVIP Helicopters with rapid fire machine guns Reconnaissance Air to air refueling Fighter Aircraft

Military airplane Refueling an airplane in mid-air Black Widow World’s Smallest Spy Aircraft Northrop B-2 Stealth Bomber

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. Business Jets These range in size from small seven-person jets like the Learjet 35A to the Boeing business jet that is based upon the 737 airliner. Most, however, seat about nine people and operate over distances of a few hundred to 1,500 miles. Far from being a luxury, today's corporate jet ferries tens of thousands of replacement parts, customers, and mid-level employees for companies of all sizes. All save time and money by using America's general aviation (GA) business fleet to avoid airlines delays and their congested hub-based route systems. Turbojet (jet) aircraft comprise 4 percent of the GA fleet. Tiltrotors These aircraft combine the vertical takeoff, hover, and landing capabilities of a helicopter with the forward speed of a turboprop. Their engines and propellers tilt up to form the rotors for vertical flight and tilt forward to create propulsion for fast forward fl

Private Aircraft Tiltrotor plane’s Crop Spraying Medical Evacuations Business Jets These range in size from small seven-person jets like the Learjet 35A to the Boeing business jet that is based upon the 737 airliner. Most, however, seat about nine people and operate over distances of a few hundred to 1,500 miles. Far from being a luxury, today's corporate jet ferries tens of thousands of replacement parts, customers, and mid-level employees for companies of all sizes. All save time and money by using America's general aviation (GA) business fleet to avoid airlines delays and their congested hub-based route systems. Turbojet (jet) aircraft comprise 4 percent of the GA fleet. Tiltrotors These aircraft combine the vertical takeoff, hover, and landing capabilities of a helicopter with the forward speed of a turboprop. Their engines and propellers tilt up to form the rotors for vertical flight and tilt forward to create propulsion for fast forward fl Medical Evacuations

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 EMPENNAGE FUSELAGE WING ENGINE

Parts of an Airplane Fuselage: 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. Straight Wing – used by small, low speed aircraft Sweepback Wing- used by most high-speed aircraft. Delta Wing-used by Supersonic Aircraft Swing Wing

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. Tail: Vertical Stabilizer , rudder (movable)-yaw control Horizontal Stabilizer , elevator (movable)-pitch control Power Plants (Engine/propeller) To generate thrust that propels the aircraft Propeller Gas Turbine Landing Gear: Conventional gear: tail wheel, two main wheels Unconventional gear: skis, skids, or floats

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.

Elevator Rudder Aileron Rudder Flaps Boeing 747 Elevator Rudder Aileron Rudder Flaps

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 Surfaces Flaps: 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 Surfaces Spoilers: 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 airplane The Four Forces in Balance Let us look more closely at the interplay between the four forces. Recall that in our model, the four forces work in oppositional pairs: lift versus weight and thrust versus drag. When forces are in balance, that is their magnitudes are the same and their directions are opposite, the speed and direction of the object will not change. Imagine an airplane, flying along at its cruising speed and its cruising altitude. The wings are creating enough lift to counteract the weight of the aircraft and keep it at its cruising altitude. The engines are creating enough thrust to counteract the drag of the aircraft and keep it at its cruising speed. Let's say that the lift force is increased or the weight of the aircraft is decreased (it's using up fuel, for instance). Now there is an imbalance between the lift force and the weight force and the airplane will ascend. Conversely if the lift force is decreased the lift force and the weight force will not be balanced and the airplane will descend. In the same way, if the thrust force is increased, an imbalance is created, and the airplane will increase its speed in the direction the thrust is directed. Similarly, if the thrust is decreased, or the drag increased (say the flaps on the wings are extended), the airplane's speed will decrease. Thus, the task of a pilot is to manage the balance between these four forces - we call this flying! 20

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. Cl=coefficient of lift Magic number of lift; determined experimentally Constant for any size wing with same airfoil Accounts for unknowns Varies with angle of attack There is an angle where the wing produces zero lift Explains how a wing can fly upside down

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 Aircraft 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……. Four forces acted on the plane Thrust generated by the engine Lift force produced by airflow to the Wing. Drag is air resistance Weight is gravitational pull Boeing 747 Lift Thrust There are four primary forces that act on an airplane in flight: thrust, weight, drag and lift. It is the interplay between these four forces that result in an airplane's motion. When an airplane is on the ground not moving, there is not enough air flowing around it to create lift. So, thrust force is needed to get the airplane moving through the air. Thrust propels an object in a particular direction. A jet engine generates thrust and, because it is attached to the wing of an airplane, its thrust will be applied to the airplane. So, as the engines thrust the airplane in the direction that they are pointed, air is flowing over its wing. The shape of the wing, or more specific, the shape of the airfoil will have a direct influence on how the air moving from front to back of the wing. Airfoil shape is more curved than the bottom. Thus, the airflow travels faster on the top and slower below the wing. According to Bernoulli’s theory, an increase in velocity leads to 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 goes up. If enough lift is generated where lift is greater than the plane’s weight, the airplane will fly. The other force is drag - Any motion or movement by the airplane will always be resisted by a drag force. Drag is the force that resists any object trying to move through a fluid. The direction of the drag force is opposite to the direction of flight. The thrust force is aligned to counter the drag force. Reducing drag is one of the main concerns of aeronautical engineers when designing aircraft.

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 Lift 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 The shape of the wing, or more specific, the shape of the airfoil will have a direct influence on how the air moving from front to back of the wing. Airfoil shape is more curved than the bottom. Thus, the airflow travels faster on the top and slower below the wing. According to Bernoulli’s theory, an increase in velocity leads to 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 goes up. If enough lift is generated where lift is greater than the plane’s weight, the airplane will fly. Faster Airflow Slower 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 Section Airfoil 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. Planform: Vertical projection of wing area Elliptical: good for high speed Straight: root stalls, but cheap to make Tapered: good stall characteristics Delta: used for supersonic flight Sweep: Angle between the lateral axis and the wing (high speed aircraft) Taper: Chord decreases as you move to the wing tip Incidence: Angle between the longitudinal axis and the wing chord 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. Lift will increase as the angle of attack is increased up to the point (usually around 17 degrees) where the aircraft stalls, the critical angle of attack. It is the angle that is formed by the chord of the airfoil and the direction of the relative wind or between the chord line and the flight path. The angle of attack changes during a flight as the pilot changes the direction of the aircraft. It is one of the factors that determines the aircraft's rate of speed through the air.

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 A yoke is, perhaps, the prototypical flight control, positioned right in front of each pilot. It controls pitch (nose up/down via pull/push inputs) and roll (left/right bank via left/right turn inputs), and may control trim, as well. However, pitch and bank can also be controlled via a stick, as in some Airbus's models. Rudder Pedals They are positioned on the floor in front of the pilots, and act on the rudder, at the tail of the aircraft. They control jaw (right/left movement via push inputs on the right/left pedal) while flying, as well as steer the aircraft on the ground 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 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 aircraf to roll to the right. Aileron deflections are necessary for smooth coordinated turns. The combination of roll and yaw causes the airplane to lean into turns

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. 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 thereby increasing the pitch angle as shown. 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 thereby decreasing the pitch angle.

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. The rudder turns the aircraft right or left, this is called yawing. To yaw right or left, the pilot steps on the rudder pedals to swivel the rudder on the tail in the direction of the turn. At the same time the pilot moves the control stick side to side to raise or lower the ailerons on the wings to produce coordinate turn. Airflow causes a force to be applied to the rudder which turns the aircraft in the direction of force.