Parts of an Aircraft and Propulsion Systems Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Parts of an Aircraft and Propulsion Systems

What is an Airplane? Aircraft Airplane More general term Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics What is an Airplane? Aircraft More general term Refers to any heavier-than-air object that is Supported by its own buoyancy Supported by the action of air on its structures Airplane Heavier-than-air craft propelled by an engine Uses aerodynamic surfaces (wings) to generate lift

Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics What is an Airplane? Every airplane is an aircraft, but not every aircraft is an airplane. Space shuttle Gliders Helicopters Space Shuttle – No engines for propulsion Gliders – No engines Helicopters – Aerodynamic surfaces are not fixed. They rotate.

Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Why So Many Types? Every modern aircraft is built for a specific purpose. Different altitudes Different speeds Different weight-carrying capacities Different performance

Why So Many Types? Jet fighters Passenger airplanes Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Why So Many Types? Jet fighters Relatively lightweight Highly maneuverable and very fast Carry small amount of weight, including fuel Must refuel on long flights Passenger airplanes Larger, carry more weight, fly longer distances Less maneuverable and slower

Why So Many Types? Wing types Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Why So Many Types? Wing types The characteristic that most readily identifies the type, performance, and purpose of an airplane is the shape of its wings. Each shape allows for premium performance at different altitudes, different speeds, and different loads which must be carried.

Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Why So Many Types? Speed The speed of sound is dependent on altitude and atmospheric conditions Mach is the term used to specify how many times the speed of sound an aircraft is traveling Subsonic: Less than Mach 1 Transonic: Mach .9 to Mach 1.5 Supersonic: All speeds above Mach 1 Hypersonic: All speeds greater than Mach 5 Another important discriminator between airplanes is speed. The suffix “sonic” refers to the speed of sound. Mach 1 is one times the speed of sound. Mach 2 is twice the speed of sound. Mach numbers less than 1 are speeds less than the speed of sound. Aircraft flying at hypersonic speeds can also be said to be flying at supersonic speeds.

Parts of an Airplane Five basic structural components Fuselage Wings Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Five basic structural components Fuselage Wings Empennage (tail structures) Propulsion system Undercarriage

Fuselage Main body structure Contains Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Fuselage Main body structure All other components are attached to it Contains Cockpit or flight deck Passenger compartment Cargo compartment Produces a little lift, but can also produce a lot of drag

Wings Most important lift-producing part of the aircraft Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Most important lift-producing part of the aircraft Also carries the fuel Designed so that the outer tips of the wings are higher than where the wings are attached to the fuselage Called the dihedral Helps keep the airplane from rolling unexpectedly

Wings Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Wings

Wing Designs Straight Wing Found mostly on small, low-speed airplanes Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Wing Designs Straight Wing Found mostly on small, low-speed airplanes Good lift at low speeds Not suited to high speeds Creates a lot of drag because the wing is perpendicular to the airflow Provides good, stable flight Cheap and can be made lighter

Wing Designs Sweepback Used on most high-speed airplanes Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Wing Designs Sweepback Used on most high-speed airplanes Less drag, but more unstable at low speeds Amount of sweep depends on the purpose of the airplane Commercial airliner has moderate sweep High speed airplanes (e.g., fighters) have moderate sweep No forward sweep wings are in mass production A commercial airliner has less drag while maintaining stability at lower speeds. Fighters are not very stable at low speeds. They take off and descend for landing at a high rate of speed.

Wing Designs Delta Wings Looks like a large triangle from above Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Wing Designs Delta Wings Looks like a large triangle from above Can reach high speeds Landing speeds are very fast Wing shape found on the supersonic transport Concord

Wing Designs Swing Wing Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Wing Designs Swing Wing This design combines the high lift characteristics of a straight wing with the ability of the sweepback wing to move at high speeds During landing and takeoff, wing swings into an almost straight position During cruise, wing swings into a sweepback Hinges that enable wings to swing are very heavy

Wing Components Trailing edge equipped with flaps Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Wing Components Trailing edge equipped with flaps Move backward and downward Increase the area of the wing and the camber of the airfoil Different from the ailerons, also located on the trailing edge of the wing When an airplane lands, it is desirable to fly as slowly as possible. Ideally for landing, an airplane would have a large wing with a very cambered airfoil. However, airfoils designed to perform well at slow speeds are not good for flying at faster speeds, and vice versa. Airplane designers have developed a set of features that allow the pilot to increase the wing area and change the airfoil shape to compensate for this.

Empennage Also known as the tail assembly Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Empennage Also known as the tail assembly Provides stability and control Two main parts Vertical stabilizer (fin) to which the rudder is attached Horizontal stabilizer to which the elevators are attached

Undercarriage Also known as the landing gear, which is made up of Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Undercarriage Also known as the landing gear, which is made up of Struts Wheels Brakes Can be fixed 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 accommodate the increased weight. The advantage to retractable landing gear is that the drag is greatly reduced when the gear is retracted. When you fly on a commercial airliner, you will notice that the pilot retracts the landing gear very soon after the airplane leaves the ground. This helps to decrease drag as the airplane ascends.

Controls Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Controls When a plane is in flight, there are three imaginary axes of rotation. These lines run through the weight center (or center of gravity) of the plane. The airplane’s rotation around the y axis is called yaw; rotation around the x axis is called pitch, and rotation around the z axis is called roll.

Controls Roll is controlled by the ailerons Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Controls Roll is controlled by the ailerons Used to raise and lower the wings Turning the control wheel left causes the left aileron to raise and lowers the right aileron. The plane rolls left. Turning the control wheel right causes the right aileron to raise and lowers the left aileron. The plane rolls right.

Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Controls Pitch is controlled by the elevators on the tail of the plane. They are controlled by the control wheel (i.e., stick). If the wheel or stick is pulled back, the elevators go up, causing the nose to point up and the plane to climb. If the wheel or stick is pushed forward, the elevators go down, causing the nose to point down and the plane to lose altitude.

Controls Yaw is controlled by the rudder. Parts of an Aircraft Gateway To Technology® Unit 4– Lesson 4.2– Aeronautics Controls Yaw is controlled by the rudder. The right foot pedal turns the rudder to the right. This action causes the tail to yaw to the left and the nose to yaw to the right. To smoothly bank a plane or to turn it left or right, the pilot uses the ailerons and the rudder together.

Propulsion Systems Gateway To Technology Unit 4– Lesson 4.2– Aeronautics Propulsion System A machine that produces thrust to push an object forward The amount of thrust depends on the mass flow through the engine and the exit velocity of the gas On airplanes, thrust is usually generated through some application of Newton's third law of action and reaction. A gas, or working fluid, is accelerated by the engine, and the reaction to this acceleration produces a force on the engine.

Airplane Propulsion Systems Gateway To Technology Unit 4– Lesson 4.2– Aeronautics Airplane Propulsion Systems Propeller Turbine (jet) engine Ramjet or Scramjet Rocket Planes

Why Are There Different Types of Engines? Propulsion Systems Gateway To Technology Unit 4– Lesson 4.2– Aeronautics Why Are There Different Types of Engines? Newton’s 1st Law Objects in motion tend to stay in motion and objects at rest tend to stay at rest unless something pushes or pulls on the object. Therefore: Thrust from the propulsion system must balance the drag when the airplane is cruising. Thrust from the propulsion system must exceed the drag for the airplane to accelerate. You must have the correct type of engine (propulsion system) to provide the correct amount of thrust.

Aircraft Motion Propulsion Systems Gateway To Technology Unit 4– Lesson 4.2– Aeronautics Aircraft Motion

Propulsion System Piston Engines and Propellers Propulsion Systems Gateway To Technology Unit 4– Lesson 4.2– Aeronautics Propulsion System Piston Engines and Propellers Remember that internal combustion (gasoline) engines require oxygen to ignite the fuel, and therefore need to fly at lower altitudes Used most commonly on smaller aircraft They generally fly slower, and at lower altitudes

Propulsion System Piston Engines and Propellers Propulsion Systems Gateway To Technology Unit 4– Lesson 4.2– Aeronautics Propulsion System Piston Engines and Propellers A propeller system takes the rotary motion from a motor and converts it into thrust. It has multiple blades attached to a central shaft, and works like a rotating screw or wing. The blades are often airfoil shaped, thus utilizing both Bernoulli’s principle and Newton’s third law to produce forward motion.

Airliners and Cargo Planes Propulsion Systems Gateway To Technology Unit 4– Lesson 4.2– Aeronautics Airliners and Cargo Planes Spend most of the time in a cruise state High engine efficiency and low fuel usage more important than excess thrust Turboprop and turbofan propulsion used on airliners and cargo planes Since thrust depends on both the amount of gas moved and the velocity, we can generate high thrust by accelerating a large mass of gas by a small amount, or by accelerating a small mass of gas by a large amount. Because of the aerodynamic efficiency of propellers and fans, it is more fuel efficient to accelerate a large mass by a small amount. That is why we find high bypass fans and turboprops on cargo planes and airliners.

Propulsion Systems Gateway To Technology Unit 4– Lesson 4.2– Aeronautics Propulsion Systems Jet propulsion is similar to the release of an inflated balloon.

Propulsion Systems Turbojet First really useful jet engine built Gateway To Technology Unit 4– Lesson 4.2– Aeronautics Propulsion Systems Turbojet First really useful jet engine built The turbojet was the first really useful jet engine to be built. The air flows into the engine through the air intak. The design of the inlet makes the air slow down and also raises the pressure. The air then goes through the compressor where sets of blades compress the air even more, greatly raising the pressure. The air then enters the combustion chamber where the fuel is added and ignited. The very hot, high pressure air rushes past the turbine blades, making them spin very fast. The turbine blades are connected back to the compressor blades by a shaft. The turbine blades take some of the energy from the air and return it to the compressor. The hot, high pressure air that gets past the turbine "jets" out the exhaust nozzle, thrusting the engine forward. Turbojets are very inefficient and noisy at subsonic speeds. Most modern plans use turbofans and turboprops.

Propulsion Systems Turbofan Turboprop Gateway To Technology Unit 4– Lesson 4.2– Aeronautics Propulsion Systems Turbofan Adds a large set of fan blades at the front of the inlet Turboprop The fan from turbofan is replaced with a propeller The fan works much like a propeller, thrusting the engine forward and pushing a large amount of air backwards. As the air is pushed back by the fan, some of it goes into the engine and some bypasses the engine. The engine that sits behind the fan is basically a turbojet. The air that goes into this engine receives the same treatment as the air that goes through the turbojet. The turboprop engine is essentially a turbofan engine where the fan is replaced by a propeller. The propeller is placed outside of the inlet.

Fighter Planes and Hypersonic Aircraft Propulsion Systems Gateway To Technology Unit 4– Lesson 4.2– Aeronautics Fighter Planes and Hypersonic Aircraft Require high excess thrust to accelerate quickly and overcome high drag associated with high speeds High thrust is more important than engine efficiency

Propulsion Systems Gateway To Technology Unit 4– Lesson 4.2– Aeronautics A ramjet is a form of jet engine which uses the engine's forward motion to compress incoming air, without a rotary compressor. Ramjets cannot provide thrust at zero airspeed, and therefore, cannot move a plane from standstill. They require a forward speed of at least half the speed of sound (Mach 0.5) A scramjet or” super combustion ramjet” uses the same principles as the ramjet. However, the minimum functional speed, requires acceleration by other means to hypersonic speed before the scramjet can become active. Ramjets slow the incoming air to a subsonic speed within the combustor. Scramjets require the airflow through the engine to be at hypersonic speed. Both function best at hypersonic (above Mach 3) speeds. NASA is currently testing the X-43 at speeds of Mach 10.

Rocket Powered Airplanes Propulsion Systems Gateway To Technology Unit 4– Lesson 4.2– Aeronautics Rocket Powered Airplanes Uses a rocket engine for propulsion Has higher speeds Propels only for a short period of time Also known as a rocket plane, it is an aircraft that uses a rocket for propulsion, sometimes in addition to air-breathing jet engines (known as Jet Assisted Take Off). They can fly at much faster speeds than a jet aircraft of similar size, but only work for a few minutes, followed by a glide. Because they are powered by a rocket which does not need oxygen from the atmosphere, they are good for very high altitude flight. They also accelerate faster, and therefore have shorter takeoffs. Unusual launch configurations From another plane Vertically – nose in the air and tail to the ground

Propulsion Systems Gateway To Technology Unit 4– Lesson 4.2– Aeronautics Rocket Propulsion Engine pushes itself forward or upward by producing thrust A rocket engine uses only propellant carried within it A rocket can operate in outer space, where there is almost no air Unlike a jet engine, which draws in outside air, a rocket engine uses only the substances carried within it. Click on 3-2-1 Liftoff to show video of rocket launch.

3 – 2 – 1 Liftoff! Propulsion Systems Gateway To Technology Unit 4– Lesson 4.2– Aeronautics 3 – 2 – 1 Liftoff!

How Do Rocket Engines Work? Propulsion Systems Gateway To Technology Unit 4– Lesson 4.2– Aeronautics How Do Rocket Engines Work? Newton’s 3rd Law: For every action there is an equal and opposite reaction. Rocket engines generate thrust by putting a gas under pressure. The gas escaping the rocket is called exhaust. As the rocket pushes the exhaust backward, the exhaust pushes the rocket forward. The vast majority of rockets are chemical rockets. The two most common types of chemical rockets are solid-propellant rockets and liquid-propellant rockets. Engineers have tested a third type of chemical rocket, called a hybrid rocket, that combines liquid and solid propellants. Electric rockets have propelled space probes and maneuvered orbiting satellites. Researchers have designed experimental nuclear rockets.

Propulsion Systems Gateway To Technology Unit 4– Lesson 4.2– Aeronautics Image Resources Microsoft, Inc. (2008). Clip art. Retrieved September 10, 2008, from http://office.microsoft.com/en-us/clipart/default.aspx National Aeronautics and Space Administration (NASA). (2008). Beginner’s guide to propulsion. Retrieved June 23, 2009, from http://www.grc.nasa.gov/WWW/K-12/airplane/bgp.html National Aeronautics and Space Administration (NASA). (2008). NASA TV Video Gallery. Retrieved June 23, 2009, from http://www.nasa.gov/multimedia/videogallery/index.html National Aeronautics and Space Administration (NASA). (2008). NASA – A closer look at the X-43 mission. Retrieved June 23, 2009, from http://www.nasa.gov/missions/research/x43-image-feature.html National Aeronautics and Space Administration (NASA). (2007). NASA – Rocket. Retrieved June 23, 2009, from http://www.nasa.gov/worldbook/rocket_worldbook.html