Register a.co.uk domain name or choose from our other domains. Did you know that 4 in 5 people prefer websites with a.co.uk extension when searching online? So, whether you're a professional just starting out online or a. Learning Unlimited Australia Pty. Box 545 Lilydale Vic 3140 Australia Telephone (03) 9725 9756 email: [email protected] Fax (03) 9723 8401. Download Semiconductor Physics And Devices 3rd Ed. Instructions for download: Click “Download” button; If the image doesnt shows you can click direct link: Semiconductor Physics And Devices 3rd Ed. An aircraft is a machine that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from.
Aircraft - Wikipedia, the free encyclopedia. Voodoo, a modified P 5. Mustang is the 2. Reno Air Race Champion. An aircraft is a machine that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil. Crewed aircraft are flown by an onboard pilot, but unmanned aerial vehicles may be remotely controlled or self- controlled by onboard computers. Aircraft may be classified by different criteria, such as lift type, aircraft propulsion, usage and others. History. Each of the two World Wars led to great technical advances. Consequently, the history of aircraft can be divided into five eras: Methods of lift. They are characterized by one or more large gasbags or canopies, filled with a relatively low- density gas such as helium, hydrogen, or hot air, which is less dense than the surrounding air. When the weight of this is added to the weight of the aircraft structure, it adds up to the same weight as the air that the craft displaces. Small hot- air balloons called sky lanterns were first invented in ancient China prior to the 3rd century BC and used primarily in cultural celebrations, and were only the second type of aircraft to fly, the first being kites which were first invented in ancient China over two thousand years ago (see Han Dynasty). A balloon was originally any aerostat, while the term airship was used for large, powered aircraft designs . The advent of powered balloons, called dirigible balloons, and later of rigid hulls allowing a great increase in size, began to change the way these words were used. Huge powered aerostats, characterized by a rigid outer framework and separate aerodynamic skin surrounding the gas bags, were produced, the Zeppelins being the largest and most famous. There were still no fixed- wing aircraft or non- rigid balloons large enough to be called airships, so . Then several accidents, such as the Hindenburg disaster in 1. Sometimes this term is applied only to non- rigid balloons, and sometimes dirigible balloon is regarded as the definition of an airship (which may then be rigid or non- rigid). The Extractive Industries of North Warwickshire Coal Mining, Brick & Tile Making, Quarries, Ironstone & Ore Extraction Two rare pieces of local coal. They have been polished and then engraved. The one on the left has the. What is now Middlesex University was originally a vision for a People's University: A polytechnic that would unite science, society and creativity, theory and practice, gas engineers and sociologists. The dynamic centre for. Non- rigid dirigibles are characterized by a moderately aerodynamic gasbag with stabilizing fins at the back. These soon became known as blimps. During the Second World War, this shape was widely adopted for tethered balloons; in windy weather, this both reduces the strain on the tether and stabilizes the balloon. The nickname blimp was adopted along with the shape. In modern times, any small dirigible or airship is called a blimp, though a blimp may be unpowered as well as powered. Heavier- than- air . This dynamic movement through the air is the origin of the term aerodyne. There are two ways to produce dynamic upthrust: aerodynamic lift, and powered lift in the form of engine thrust. Aerodynamic lift involving wings is the most common, with fixed- wing aircraft being kept in the air by the forward movement of wings, and rotorcraft by spinning wing- shaped rotors sometimes called rotary wings. A wing is a flat, horizontal surface, usually shaped in cross- section as an aerofoil. To fly, air must flow over the wing and generate lift. A flexible wing is a wing made of fabric or thin sheet material, often stretched over a rigid frame. A kite is tethered to the ground and relies on the speed of the wind over its wings, which may be flexible or rigid, fixed, or rotary. With powered lift, the aircraft directs its engine thrust vertically downward. V/STOL aircraft, such as the Harrier Jump Jet and F- 3. B take off and land vertically using powered lift and transfer to aerodynamic lift in steady flight. A pure rocket is not usually regarded as an aerodyne, because it does not depend on the air for its lift (and can even fly into space); however, many aerodynamic lift vehicles have been powered or assisted by rocket motors. Rocket- powered missiles that obtain aerodynamic lift at very high speed due to airflow over their bodies are a marginal case. Fixed- wing. Whereas a fixed- wing aircraft relies on its forward speed to create airflow over the wings, a kite is tethered to the ground and relies on the wind blowing over its wings to provide lift. Kites were the first kind of aircraft to fly, and were invented in China around 5. BC. Much aerodynamic research was done with kites before test aircraft, wind tunnels, and computer modelling programs became available. The first heavier- than- air craft capable of controlled free- flight were gliders. A glider designed by Cayley carried out the first true manned, controlled flight in 1. Practical, powered, fixed- wing aircraft (the aeroplane or airplane) were invented by Wilbur and Orville Wright. Besides the method of propulsion, fixed- wing aircraft are in general characterized by their wing configuration. The most important wing characteristics are: Number of wings . The opposite of this is a lifting body, which has no wings, though it may have small stabilizing and control surfaces. Wing- in- ground- effect vehicles are not considered aircraft. An example is the Russian ekranoplan (nicknamed the . Man- powered aircraft also rely on ground effect to remain airborne with a minimal pilot power, but this is only because they are so underpowered . Types include helicopters, autogyros, and various hybrids such as gyrodynes and compound rotorcraft. Helicopters have a rotor turned by an engine- driven shaft. The rotor pushes air downward to create lift. By tilting the rotor forward, the downward flow is tilted backward, producing thrust for forward flight. Some helicopters have more than one rotor and a few have rotors turned by gas jets at the tips. Autogyros have unpowered rotors, with a separate power plant to provide thrust. The rotor is tilted backward. As the autogyro moves forward, air blows upward across the rotor, making it spin. This spinning increases the speed of airflow over the rotor, to provide lift. Rotor kites are unpowered autogyros, which are towed to give them forward speed or tethered to a static anchor in high- wind for kited flight. Cyclogyros rotate their wings about a horizontal axis. Compound rotorcraft have wings that provide some or all of the lift in forward flight. They are nowadays classified as powered lift types and not as rotorcraft. Tiltrotor aircraft (such as the V- 2. Osprey), tiltwing, tailsitter, and coleopter aircraft have their rotors/propellers horizontal for vertical flight and vertical for forward flight. Other methods of lift. If there are any wings, they are too small to provide significant lift and are used only for stability and control. Lifting bodies are not efficient: they suffer from high drag, and must also travel at high speed to generate enough lift to fly. Many of the research prototypes, such as the Martin- Marietta X- 2. Space Shuttle, were lifting bodies (though the shuttle itself is not), and some supersonicmissiles obtain lift from the airflow over a tubular body. Powered lift types rely on engine- derived lift for vertical takeoff and landing (VTOL). Most types transition to fixed- wing lift for horizontal flight. Classes of powered lift types include VTOL jet aircraft (such as the Harrier jump- jet) and tiltrotors (such as the V- 2. Osprey), among others. A few experimental designs rely entirely on engine thrust to provide lift throughout the whole flight, including personal fan- lift hover platforms and jetpacks. VTOL research designs include the flying Bedstead. The Flettner airplane uses a rotating cylinder in place of a fixed wing, obtaining lift from the magnus effect. The ornithopter obtains thrust by flapping its wings. Propulsion. Take- off may be by launching forward and downward from a high location, or by pulling into the air on a tow- line, either by a ground- based winch or vehicle, or by a powered . For a glider to maintain its forward air speed and lift, it must descend in relation to the air (but not necessarily in relation to the ground). Many gliders can 'soar' . The first practical, controllable example was designed and built by the British scientist and pioneer George Cayley, whom many recognise as the first aeronautical engineer. Common examples of gliders are sailplanes, hang gliders and paragliders. Balloons drift with the wind, though normally the pilot can control the altitude, either by heating the air or by releasing ballast, giving some directional control (since the wind direction changes with altitude). A wing- shaped hybrid balloon can glide directionally when rising or falling; but a spherically shaped balloon does not have such directional control. Kites are aircraft. Kytoons are balloon- kite hybrids that are shaped and tethered to obtain kiting deflections, and can be lighter- than- air, neutrally buoyant, or heavier- than- air. Powered aircraft. Most aircraft engines are either lightweight piston engines or gas turbines. Engine fuel is stored in tanks, usually in the wings but larger aircraft also have additional fuel tanks in the fuselage. Propeller aircraft. The propeller is usually mounted in front of the power source in tractor configuration but can be mounted behind in pusher configuration. Variations of propeller layout include contra- rotating propellers and ducted fans. Many kinds of power plant have been used to drive propellers. Early airships used man power or steam engines. The more practical internal combustion piston engine was used for virtually all fixed- wing aircraft until World War II and is still used in many smaller aircraft. Some types use turbine engines to drive a propeller in the form of a turboprop or propfan. Human- powered flight has been achieved, but has not become a practical means of transport. Unmanned aircraft and models have also used power sources such as electric motors and rubber bands. Jet aircraft. An afterburner may be used to inject extra fuel into the hot exhaust, especially on military . Use of a turbine is not absolutely necessary: other designs include the pulse jet and ramjet.
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