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81-474: The main purpose of the IFCS project is to create a system for use in civilian and military aircraft that is both adaptive and fault tolerant . This is accomplished through the use of upgrades to the flight control software that incorporate self-learning neural network technology. The goals of the IFCS neural network project are. The neural network of the IFCS learns flight characteristics in real time through

162-402: A buoyant force that does not require lateral movement through the surrounding air mass to effect a lifting force. By contrast, aerodynes primarily use aerodynamic lift , which requires the lateral movement of at least some part of the aircraft through the surrounding air mass. Some things that fly do not generate propulsive thrust through the air, for example, the flying squirrel . This

243-404: A combustion chamber , and accelerate the exhaust rearwards to provide thrust. Different jet engine configurations include the turbojet and turbofan , sometimes with the addition of an afterburner . Those with no rotating turbomachinery include the pulsejet and ramjet . These mechanically simple engines produce no thrust when stationary, so the aircraft must be launched to flying speed using

324-433: A lifting gas such as helium , hydrogen or hot air , which is less dense than the surrounding air. When the weight of the lifting gas is added to the weight of the aircraft itself, it is same or less than the mass of 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

405-455: A rocket launch , which provides the initial thrust to overcome the force of gravity and propels the spacecraft from the surface of the Earth. Once in space, the motion of a spacecraft—both when unpropelled and when under propulsion—is covered by the area of study called astrodynamics . Some spacecraft remain in space indefinitely, some disintegrate during atmospheric reentry , and others reach

486-560: A catapult, like the V-1 flying bomb , or a rocket, for example. Other engine types include the motorjet and the dual-cycle Pratt & Whitney J58 . Compared to engines using propellers, jet engines can provide much higher thrust, higher speeds and, above about 40,000 ft (12,000 m), greater efficiency. They are also much more fuel-efficient than rockets . As a consequence nearly all large, high-speed or high-altitude aircraft use jet engines. Some rotorcraft, such as helicopters , have

567-642: A flying fish was 45 seconds. Most birds fly ( see bird flight ), with some exceptions. The largest birds, the ostrich and the emu , are earthbound flightless birds , as were the now-extinct dodos and the Phorusrhacids , which were the dominant predators of South America in the Cenozoic era. The non-flying penguins have wings adapted for use under water and use the same wing movements for swimming that most other birds use for flight. Most small flightless birds are native to small islands, and lead

648-638: A greater wingspan (94m/260 ft) than any current aircraft and a tail height equal to the tallest (Airbus A380-800 at 24.1m/78 ft) — flew only one short hop in the late 1940s and never flew out of ground effect . The largest civilian airplanes, apart from the above-noted An-225 and An-124, are the Airbus Beluga cargo transport derivative of the Airbus A300 jet airliner, the Boeing Dreamlifter cargo transport derivative of

729-427: A heavier aircraft gliding at a higher airspeed will arrive at the same touchdown point in a shorter time. Air pressure acting up against an object in air is greater than the pressure above pushing down. The buoyancy, in both cases, is equal to the weight of fluid displaced - Archimedes' principle holds for air just as it does for water. A cubic meter of air at ordinary atmospheric pressure and room temperature has

810-564: A lifestyle where flight would offer little advantage. Among living animals that fly, the wandering albatross has the greatest wingspan, up to 3.5 meters (11 feet); the great bustard has the greatest weight, topping at 21 kilograms (46 pounds). Most species of insects can fly as adults. Insect flight makes use of either of two basic aerodynamic models: creating a leading edge vortex, found in most insects, and using clap and fling , found in very small insects such as thrips . Many species of spiders , spider mites and lepidoptera use

891-674: A marginal case. The forerunner of the fixed-wing aircraft is the kite . 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 500 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 George Cayley carried out

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972-411: A mass of about 1.2 kilograms, so its weight is about 12 newtons . Therefore, any 1-cubic-meter object in air is buoyed up with a force of 12 newtons. If the mass of the 1-cubic-meter object is greater than 1.2 kilograms (so that its weight is greater than 12 newtons), it falls to the ground when released. If an object of this size has a mass less than 1.2 kilograms, it rises in the air. Any object that has

1053-605: A mass that is less than the mass of an equal volume of air will rise in air - in other words, any object less dense than air will rise. Thrust-to-weight ratio is, as its name suggests, the ratio of instantaneous thrust to weight (where weight means weight at the Earth 's standard acceleration g 0 {\displaystyle g_{0}} ). It is a dimensionless parameter characteristic of rockets and other jet engines and of vehicles propelled by such engines (typically space launch vehicles and jet aircraft ). If

1134-794: A maximum loaded weight of 550–700 t (1,210,000–1,540,000 lb), it was also the heaviest aircraft built to date. It could cruise at 500 mph (800 km/h; 430 kn). The aircraft was destroyed during the Russo-Ukrainian War . The largest military airplanes are the Ukrainian Antonov An-124 Ruslan (world's second-largest airplane, also used as a civilian transport), and American Lockheed C-5 Galaxy transport, weighing, loaded, over 380 t (840,000 lb). The 8-engine, piston/propeller Hughes H-4 Hercules "Spruce Goose" — an American World War II wooden flying boat transport with

1215-470: A pair of flat gliding surfaces. "Flying" snakes also use mobile ribs to flatten their body into an aerodynamic shape, with a back and forth motion much the same as they use on the ground. Flying fish can glide using enlarged wing-like fins, and have been observed soaring for hundreds of meters. It is thought that this ability was chosen by natural selection because it was an effective means of escape from underwater predators. The longest recorded flight of

1296-569: A payload of up to 22,050 lb (10,000 kg). The largest aircraft by weight and largest regular fixed-wing aircraft ever built, as of 2016 , was the Antonov An-225 Mriya . That Soviet-built ( Ukrainian SSR ) six-engine transport of the 1980s was 84 m (276 ft) long, with an 88 m (289 ft) wingspan. It holds the world payload record, after transporting 428,834 lb (194,516 kg) of goods, and has flown 100 t (220,000 lb) loads commercially. With

1377-539: A planetary or lunar surface for landing or impact. In 2018, researchers at Massachusetts Institute of Technology (MIT) managed to fly an aeroplane with no moving parts, powered by an " ionic wind" also known as electroaerodynamic thrust. Many human cultures have built devices that fly, from the earliest projectiles such as stones and spears, the boomerang in Australia , the hot air Kongming lantern , and kites . George Cayley studied flight scientifically in

1458-588: A powered "tug" aircraft. 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", i.e. , gain height from updrafts such as thermal currents. 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

1539-491: A powered rotary wing or rotor , where the rotor disc can be angled slightly forward so that a proportion of its lift is directed forwards. The rotor may, like a propeller, be powered by a variety of methods such as a piston engine or turbine. Experiments have also used jet nozzles at the rotor blade tips . Aircraft are designed according to many factors such as customer and manufacturer demand, safety protocols and physical and economic constraints. For many types of aircraft

1620-632: A reality in the 20th century following theoretical and practical breakthroughs by Konstantin Tsiolkovsky and Robert H. Goddard . The first orbital spaceflight was in 1957, and Yuri Gagarin was carried aboard the first crewed orbital spaceflight in 1961. There are different approaches to flight. If an object has a lower density than air, then it is buoyant and is able to float in the air without expending energy. A heavier than air craft, known as an aerodyne , includes flighted animals and insects, fixed-wing aircraft and rotorcraft . Because

1701-458: A retarding force called drag. Because lift and drag are both aerodynamic forces, the ratio of lift to drag is an indication of the aerodynamic efficiency of the airplane. The lift to drag ratio is the L/D ratio, pronounced "L over D ratio." An airplane has a high L/D ratio if it produces a large amount of lift or a small amount of drag. The lift/drag ratio is determined by dividing the lift coefficient by

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1782-577: A rigid basket or gondola slung below it to carry its payload. Early aircraft, including airships , often employed flexible doped aircraft fabric covering to give a reasonably smooth aeroshell stretched over a rigid frame. Later aircraft employed semi- monocoque techniques, where the skin of the aircraft is stiff enough to share much of the flight loads. In a true monocoque design there is no internal structure left. The key structural parts of an aircraft depend on what type it is. Lighter-than-air types are characterised by one or more gasbags, typically with

1863-420: A supporting structure of flexible cables or a rigid framework called its hull. Other elements such as engines or a gondola may also be attached to the supporting structure. Heavier-than-air types are characterised by one or more wings and a central fuselage . The fuselage typically also carries a tail or empennage for stability and control, and an undercarriage for takeoff and landing. Engines may be located on

1944-465: A technique called ballooning to ride air currents such as thermals , by exposing their gossamer threads which gets lifted by wind and atmospheric electric fields . Mechanical flight is the use of a machine to fly. These machines include aircraft such as airplanes , gliders , helicopters , autogyros , airships , balloons , ornithopters as well as spacecraft . Gliders are capable of unpowered flight. Another form of mechanical flight

2025-418: Is perpendicular to the flow direction. Aerodynamic lift results when the wing causes the surrounding air to be deflected - the air then causes a force on the wing in the opposite direction, in accordance with Newton's third law of motion . Lift is commonly associated with the wing of an aircraft , although lift is also generated by rotors on rotorcraft (which are effectively rotating wings, performing

2106-522: Is a lifting body , which has no wings, though it may have small stabilizing and control surfaces. Wing-in-ground-effect vehicles are generally not considered aircraft. They "fly" efficiently close to the surface of the ground or water, like conventional aircraft during takeoff. An example is the Russian ekranoplan nicknamed the " Caspian Sea Monster ". Man-powered aircraft also rely on ground effect to remain airborne with minimal pilot power, but this

2187-437: Is a powered one. A powered, steerable aerostat is called a dirigible . 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). Non-rigid dirigibles are characterized by a moderately aerodynamic gasbag with stabilizing fins at the back. These soon became known as blimps . During World War II , this shape

2268-439: Is a system that remains aloft primarily through the use of buoyancy to give an aircraft the same overall density as air. Aerostats include free balloons , airships , and moored balloons . An aerostat's main structural component is its envelope , a lightweight skin that encloses a volume of lifting gas to provide buoyancy , to which other components are attached. Aerostats are so named because they use "aerostatic" lift,

2349-409: Is able to fly by gaining support from the air . It counters the force of gravity by using either static lift or the dynamic lift of an airfoil , or, in a few cases, direct downward thrust from its engines. Common examples of aircraft include airplanes , helicopters , airships (including blimps ), gliders , paramotors , and hot air balloons . The human activity that surrounds aircraft

2430-478: Is called aviation . The science of aviation, including designing and building aircraft, is called aeronautics . Crewed aircraft are flown by an onboard pilot , whereas 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 (if any), usage and others. Flying model craft and stories of manned flight go back many centuries; however,

2511-404: Is equal to the drag D divided by the (density r times half the velocity V squared times the reference area A). [Cd = D / (A * .5 * r * V^2)] Lift-to-drag ratios for practical aircraft vary from about 4:1 for vehicles and birds with relatively short wings, up to 60:1 or more for vehicles with very long wings, such as gliders. A greater angle of attack relative to the forward movement also increases

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2592-413: Is flight faster than the speed of sound . Supersonic flight is associated with the formation of shock waves that form a sonic boom that can be heard from the ground, and is frequently startling. The creation of this shockwave requires a significant amount of energy; because of this, supersonic flight is generally less efficient than subsonic flight at about 85% of the speed of sound. Hypersonic flight

2673-494: Is known as the Intelligent Autopilot System which has Artificial Neural Networks capable of learning from human teachers by imitation. The system is capable of handling severe weather conditions and flight emergencies such as engine failure or fire, emergency landing, and performing Rejected Take Off (RTO) in a flight simulator. Aircraft An aircraft ( pl. : aircraft) is a vehicle that

2754-1066: Is normally called the powerplant , and includes engine or motor , propeller or rotor , (if any), jet nozzles and thrust reversers (if any), and accessories essential to the functioning of the engine or motor (e.g.: starter , ignition system , intake system , exhaust system , fuel system , lubrication system, engine cooling system , and engine controls ). Powered aircraft are typically powered by internal combustion engines ( piston or turbine ) burning fossil fuels —typically gasoline ( avgas ) or jet fuel . A very few are powered by rocket power , ramjet propulsion, or by electric motors , or by internal combustion engines of other types, or using other fuels. A very few have been powered, for short flights, by human muscle energy (e.g.: Gossamer Condor ). The avionics comprise any electronic aircraft flight control systems and related equipment, including electronic cockpit instrumentation, navigation, radar , monitoring, and communications systems . Flight Flight or flying

2835-452: Is only because they are so underpowered—in fact, the airframe is capable of flying higher. Rotorcraft, or rotary-wing aircraft, use a spinning rotor with aerofoil cross-section blades (a rotary wing ) to provide lift. 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

2916-440: Is para-sailing, where a parachute-like object is pulled by a boat. In an airplane, lift is created by the wings; the shape of the wings of the airplane are designed specially for the type of flight desired. There are different types of wings: tempered, semi-tempered, sweptback, rectangular and elliptical. An aircraft wing is sometimes called an airfoil , which is a device that creates lift when air flows across it. Supersonic flight

2997-450: Is pushed in the direction opposite to flight. This can be done in several ways including by the spinning blades of a propeller , or a rotating fan pushing air out from the back of a jet engine , or by ejecting hot gases from a rocket engine . The forward thrust is proportional to the mass of the airstream multiplied by the difference in velocity of the airstream. Reverse thrust can be generated to aid braking after landing by reversing

3078-623: Is stored in tanks, usually in the wings but larger aircraft also have additional fuel tanks in the fuselage . Propeller aircraft use one or more propellers (airscrews) to create thrust in a forward direction. 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

3159-648: Is termed ballistic flight . Examples include balls , arrows , bullets , fireworks etc. Essentially an extreme form of ballistic flight, spaceflight is the use of space technology to achieve the flight of spacecraft into and through outer space . Examples include ballistic missiles , orbital spaceflight , etc. Spaceflight is used in space exploration , and also in commercial activities like space tourism and satellite telecommunications . Additional non-commercial uses of spaceflight include space observatories , reconnaissance satellites and other Earth observation satellites . A spaceflight typically begins with

3240-493: Is termed gliding . Some other things can exploit rising air to climb such as raptors (when gliding) and man-made sailplane gliders . This is termed soaring . However most other birds and all powered aircraft need a source of propulsion to climb. This is termed powered flight. The only groups of living things that use powered flight are birds , insects , and bats , while many groups have evolved gliding. The extinct pterosaurs , an order of reptiles contemporaneous with

3321-475: Is the Lockheed SR-71 Blackbird , a U.S. reconnaissance jet fixed-wing aircraft, having reached 3,530 km/h (2,193 mph) on 28 July 1976. Gliders are heavier-than-air aircraft that do not employ propulsion once airborne. 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

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3402-784: Is the process by which an object moves through a space without contacting any planetary surface , either within an atmosphere (i.e. air flight or aviation ) or through the vacuum of outer space (i.e. spaceflight ). This can be achieved by generating aerodynamic lift associated with gliding or propulsive thrust , aerostatically using buoyancy , or by ballistic movement. Many things can fly, from animal aviators such as birds , bats and insects , to natural gliders/parachuters such as patagial animals, anemochorous seeds and ballistospores , to human inventions like aircraft ( airplanes , helicopters , airships , balloons , etc.) and rockets which may propel spacecraft and spaceplanes . The engineering aspects of flight are

3483-462: Is very high speed flight where the heat generated by the compression of the air due to the motion through the air causes chemical changes to the air. Hypersonic flight is achieved primarily by reentering spacecraft such as the Space Shuttle and Soyuz . Some things generate little or no lift and move only or mostly under the action of momentum, gravity, air drag and in some cases thrust. This

3564-629: The Bell Boeing V-22 Osprey ), tiltwing , tail-sitter , and coleopter aircraft have their rotors/ propellers horizontal for vertical flight and vertical for forward flight. The smallest aircraft are toys/recreational items, and nano aircraft . The largest aircraft by dimensions and volume (as of 2016) is the 302 ft (92 m) long British Airlander 10 , a hybrid blimp, with helicopter and fixed-wing features, and reportedly capable of speeds up to 90 mph (140 km/h; 78 kn), and an airborne endurance of two weeks with

3645-631: The Boeing 747 jet airliner/transport (the 747-200B was, at its creation in the 1960s, the heaviest aircraft ever built, with a maximum weight of over 400 t (880,000 lb)), and the double-decker Airbus A380 "super-jumbo" jet airliner (the world's largest passenger airliner). The fastest fixed-wing aircraft and fastest glider, is the Space Shuttle , which re-entered the atmosphere at nearly Mach 25 or 17,500 mph (28,200 km/h) The fastest recorded powered aircraft flight and fastest recorded aircraft flight of an air-breathing powered aircraft

3726-637: The Harrier jump jet and Lockheed Martin F-35B 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 its flight does not depend on interaction with the air at all (and thus can even fly in the vacuum of outer 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

3807-451: The aircraft ’s sensors and from error corrections from the primary flight computer , and then uses this information to create different flight characteristic models for the aircraft. The neural network only learns when the aircraft is in a stable flight condition, and will discard any characteristics that would cause the aircraft to go into a failure condition. If the aircraft's condition changes from stable to failure, for example, if one of

3888-400: The control surfaces becomes damaged and unresponsive, the IFCS can detect this fault and switch the flight characteristic model for the aircraft. The neural network then works to drive the error between the reference model and the actual aircraft state to zero. Generation 1 IFCS flight tests were conducted in 2003 to test the outputs of the neural network. In this phase, the neural network

3969-529: The dinosaurs , were also very successful flying animals, and there were apparently some flying dinosaurs (see Flying and gliding animals#Non-avian dinosaurs ). Each of these groups' wings evolved independently , with insects the first animal group to evolve flight. The wings of the flying vertebrate groups are all based on the forelimbs, but differ significantly in structure; insect wings are hypothesized to be highly modified versions of structures that form gills in most other groups of arthropods . Bats are

4050-482: The thrust-to-weight ratio is greater than the local gravity strength (expressed in g s), then flight can occur without any forward motion or any aerodynamic lift being required. If the thrust-to-weight ratio times the lift-to-drag ratio is greater than local gravity then takeoff using aerodynamic lift is possible. Flight dynamics is the science of air and space vehicle orientation and control in three dimensions. The three critical flight dynamics parameters are

4131-435: The 1930s, large intercontinental flying boats were also sometimes referred to as "ships of the air" or "flying-ships".  — though none had yet been built. 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

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4212-470: The aircraft's weight. There are two ways to produce dynamic upthrust — aerodynamic lift by having air flowing past an aerofoil (such dynamic interaction of aerofoils with air is the origin of the term "aerodyne"), or powered lift in the form of reactional lift from downward engine thrust . Aerodynamic lift involving wings is the most common, and can be achieved via two methods. Fixed-wing aircraft ( airplanes and gliders ) achieve airflow past

4293-601: The angles of rotation in three dimensions about the vehicle's center of mass , known as pitch , roll and yaw (See Tait-Bryan rotations for an explanation). The control of these dimensions can involve a horizontal stabilizer (i.e. "a tail"), ailerons and other movable aerodynamic devices which control angular stability i.e. flight attitude (which in turn affects altitude , heading ). Wings are often angled slightly upwards- they have "positive dihedral angle " which gives inherent roll stabilization. To create thrust so as to be able to gain height, and to push through

4374-501: 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. 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

4455-400: The car stable on the road. For a solid object moving through a fluid, the drag is the component of the net aerodynamic or hydrodynamic force acting opposite to the direction of the movement. Therefore, drag opposes the motion of the object, and in a powered vehicle it must be overcome by thrust . The process which creates lift also causes some drag. Aerodynamic lift is created by

4536-486: The craft is heavier than air, it must generate lift to overcome its weight . The wind resistance caused by the craft moving through the air is called drag and is overcome by propulsive thrust except in the case of gliding . Some vehicles also use thrust in the place of lift; for example rockets and Harrier jump jets . Forces relevant to flight are These forces must be balanced for stable flight to occur. A fixed-wing aircraft generates forward thrust when air

4617-435: The design process is regulated by national airworthiness authorities. The key parts of an aircraft are generally divided into three categories: The approach to structural design varies widely between different types of aircraft. Some, such as paragliders, comprise only flexible materials that act in tension and rely on aerodynamic pressure to hold their shape. A balloon similarly relies on internal gas pressure, but may have

4698-443: The drag coefficient, CL/CD. The lift coefficient Cl is equal to the lift L divided by the (density r times half the velocity V squared times the wing area A). [Cl = L / (A * .5 * r * V^2)] The lift coefficient is also affected by the compressibility of the air, which is much greater at higher speeds, so velocity V is not a linear function. Compressibility is also affected by the shape of the aircraft surfaces. The drag coefficient Cd

4779-411: The extent of deflection, and thus generates extra lift. However a greater angle of attack also generates extra drag. Lift/drag ratio also determines the glide ratio and gliding range. Since the glide ratio is based only on the relationship of the aerodynamics forces acting on the aircraft, aircraft weight will not affect it. The only effect weight has is to vary the time that the aircraft will glide for –

4860-462: The first half of the 19th century, and in the second half of the 19th century Otto Lilienthal made over 200 gliding flights and was also one of the first to understand flight scientifically. His work was replicated and extended by the Wright brothers who made gliding flights and finally the first controlled and extended, manned powered flights. Spaceflight, particularly human spaceflight became

4941-477: The first manned ascent — and safe descent — in modern times took place by larger hot-air balloons developed in the 18th century. Each of the two World Wars led to great technical advances. Consequently, the history of aircraft can be divided into five eras: Lighter-than-air aircraft or aerostats use buoyancy to float in the air in much the same way that ships float on the water. They are characterized by one or more large cells or canopies, filled with

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5022-532: The first true manned, controlled flight in 1853. The first powered and controllable fixed-wing aircraft (the airplane or aeroplane) was invented by Wilbur and Orville Wright . Besides the method of propulsion (if any), fixed-wing aircraft are in general characterized by their wing configuration . The most important wing characteristics are: A variable geometry aircraft can change its wing configuration during flight. A flying wing has no fuselage, though it may have small blisters or pods. The opposite of this

5103-418: The fuselage or wings. On a fixed-wing aircraft the wings are rigidly attached to the fuselage, while on a rotorcraft the wings are attached to a rotating vertical shaft. Smaller designs sometimes use flexible materials for part or all of the structure, held in place either by a rigid frame or by air pressure. The fixed parts of the structure comprise the airframe . The source of motive power for an aircraft

5184-514: 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 "airship" came to be synonymous with these aircraft. Then several accidents, such as the Hindenburg disaster in 1937, led to the demise of these airships. Nowadays a "balloon" is an unpowered aerostat and an "airship"

5265-663: The motion of an aerodynamic object (wing) through the air, which due to its shape and angle deflects the air. For sustained straight and level flight, lift must be equal and opposite to weight. In general, long narrow wings are able deflect a large amount of air at a slow speed, whereas smaller wings need a higher forward speed to deflect an equivalent amount of air and thus generate an equivalent amount of lift. Large cargo aircraft tend to use longer wings with higher angles of attack, whereas supersonic aircraft tend to have short wings and rely heavily on high forward speed to generate lift. However, this lift (deflection) process inevitably causes

5346-408: The neural network adjusts the outputs of the primary flight computer through a dynamic inversion controller to bring the difference to zero before they are sent to the actuator control electronics which move the control surfaces. A different research and development project with the goal of designing an intelligent flight control system is being carried out at University College London. Their prototype

5427-427: The only mammals capable of sustaining level flight (see bat flight ). However, there are several gliding mammals which are able to glide from tree to tree using fleshy membranes between their limbs; some can travel hundreds of meters in this way with very little loss in height. Flying frogs use greatly enlarged webbed feet for a similar purpose, and there are flying lizards which fold out their mobile ribs into

5508-410: The pitch of variable-pitch propeller blades, or using a thrust reverser on a jet engine. Rotary wing aircraft and thrust vectoring V/STOL aircraft use engine thrust to support the weight of the aircraft, and vector sum of this thrust fore and aft to control forward speed. In the context of an air flow relative to a flying body, the lift force is the component of the aerodynamic force that

5589-410: The purview of aerospace engineering which is subdivided into aeronautics , the study of vehicles that travel through the atmosphere, and astronautics , the study of vehicles that travel through space, and ballistics , the study of the flight of projectiles. Humans have managed to construct lighter-than-air vehicles that raise off the ground and fly, due to their buoyancy in the air. An aerostat

5670-411: 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. Some have a tail rotor to counteract the rotation of the main rotor, and to aid directional control. Autogyros have unpowered rotors, with a separate power plant to provide thrust. The rotor is tilted backward. As

5751-427: The same function without requiring that the aircraft move forward through the air). While common meanings of the word " lift " suggest that lift opposes gravity, aerodynamic lift can be in any direction. When an aircraft is cruising for example, lift does oppose gravity, but lift occurs at an angle when climbing, descending or banking. On high-speed cars, the lift force is directed downwards (called "down-force") to keep

5832-436: The second type of aircraft to fly, the first being kites , which were also 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 — usually fixed-wing. In 1919, Frederick Handley Page was reported as referring to "ships of the air," with smaller passenger types as "Air yachts." In

5913-530: The tether or kite line ; they rely on virtual or real wind blowing over and under them to generate lift and drag. 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 have one or more onboard sources of mechanical power, typically aircraft engines although rubber and manpower have also been used. Most aircraft engines are either lightweight reciprocating engines or gas turbines . Engine fuel

5994-410: The theory of operation. It is a direct adaptive system that continuously provides error corrections and then measures the effects of these corrections in order to learn new flight models or adjust existing ones. To measure the aircraft state, the neural network takes 31 inputs from the roll, pitch, and yaw axes and the control surfaces . If there is a difference between the aircraft state and model,

6075-460: 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 that are tethered to the ground or other object (fixed or mobile) that maintains tension in

6156-431: The wing. A flexible wing is a wing made of fabric or thin sheet material, often stretched over a rigid frame, similar to the flight membranes on many flying and gliding animals . 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

6237-402: The wings by having the entire aircraft moving forward through the air, while rotorcraft ( helicopters and autogyros ) do so by having mobile, elongated wings spinning rapidly around a mast in an assembly known as the rotor . As aerofoils, there must be air flowing over the wing to create pressure difference between above and below, thus generating upward lift over the entire wetted area of

6318-675: Was of the NASA X-43 A Pegasus , a scramjet -powered, hypersonic , lifting body experimental research aircraft, at Mach 9.68 or 6,755 mph (10,870 km/h) on 16 November 2004. Prior to the X-43A, the fastest recorded powered airplane flight, and still the record for the fastest manned powered airplane, was the North American X-15 , rocket-powered airplane at Mach 6.7 or 7,274 km/h (4,520 mph) on 3 October 1967. The fastest manned, air-breathing powered airplane

6399-487: Was pre-trained using flight characteristics obtained for the McDonnell Douglas F-15 STOL/MTD in a wind tunnel test and did not actually provide any control adjustments in flight. The outputs of the neural network were run directly to instrumentation for data collection purposes only. Generation 2 IFCS tests were conducted in 2005 and used a fully integrated neural network as described in

6480-490: 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 use airbreathing jet engines , which take in air, burn fuel with it in

6561-439: 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 aircraft or aerodynes are denser than air and thus must find some way to obtain enough lift that can overcome

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