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Aircraft	849		An aircraft (pl.: aircraft) is a vehicle that 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.
Aircraft	849		The human activity that surrounds aircraft 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.
Aircraft	849	History	Flying model craft and stories of manned flight go back many centuries; however, 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:
Aircraft	849	Methods of lift	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 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.
Aircraft	849	Methods of lift	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).
Aircraft	849	Methods of lift	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 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 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" is a powered one.
Aircraft	849	Methods of lift	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 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.
Aircraft	849	Methods of lift	Heavier-than-air aircraft, such as airplanes, must find some way to push air or gas downwards so that a reaction occurs (by Newton's laws of motion) to push the aircraft upwards. This dynamic movement through the air is the origin of the term. There are two ways to produce dynamic upthrust — aerodynamic lift, and powered lift in the form of engine thrust.
Aircraft	849	Methods of lift	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.
Aircraft	849	Methods of lift	With powered lift, the aircraft directs its engine thrust vertically downward. V/STOL aircraft, such as 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.
Aircraft	849	Methods of lift	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.
Aircraft	849	Methods of lift	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.
Aircraft	849	Methods of lift	The first heavier-than-air craft capable of controlled free-flight were gliders. A glider designed by George Cayley carried out 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.
Aircraft	849	Methods of lift	Besides the method of propulsion (if any), fixed-wing aircraft are in general characterized by their wing configuration. The most important wing characteristics are:
Aircraft	849	Methods of lift	A variable geometry aircraft can change its wing configuration during flight.
Aircraft	849	Methods of lift	A flying wing has no fuselage, though it may have small blisters or pods. The opposite of this is a lifting body, which has no wings, though it may have small stabilizing and control surfaces.
Aircraft	849	Methods of lift	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 is only because they are so underpowered—in fact, the airframe is capable of flying higher.
Aircraft	849	Methods of lift	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.
Aircraft	849	Methods of lift	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. Some have a tail rotor to counteract the rotation of the main rotor, and to aid directional control.
Aircraft	849	Methods of lift	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.
Aircraft	849	Methods of lift	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 Bell Boeing V-22 Osprey), tiltwing, tail-sitter, and coleopter aircraft have their rotors/propellers horizontal for vertical flight and vertical for forward flight.
Aircraft	849	Size and speed extremes	The smallest aircraft are toys/recreational items, and nano aircraft.
Aircraft	849	Size and speed extremes	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 a payload of up to 22,050 lb (10,000 kg).
Aircraft	849	Size and speed extremes	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 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.
Aircraft	849	Size and speed extremes	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 a greater wingspan (94m/260ft) than any current aircraft and a tail height equal to the tallest (Airbus A380-800 at 24.1m/78ft) — flew only one short hop in the late 1940s and never flew out of ground effect.
Aircraft	849	Size and speed extremes	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 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).
Aircraft	849	Size and speed extremes	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)
Aircraft	849	Size and speed extremes	The fastest recorded powered aircraft flight and fastest recorded aircraft flight of an air-breathing powered aircraft was of the NASA X-43A 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.
Aircraft	849	Size and speed extremes	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.
Aircraft	849	Size and speed extremes	The fastest manned, air-breathing powered airplane 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.
Aircraft	849	Propulsion	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 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.
Aircraft	849	Propulsion	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.
Aircraft	849	Propulsion	Kites are aircraft that are tethered to the ground or other object (fixed or mobile) that maintains tension in 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.
Aircraft	849	Propulsion	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 is stored in tanks, usually in the wings but larger aircraft also have additional fuel tanks in the fuselage.
Aircraft	849	Propulsion	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.
Aircraft	849	Propulsion	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.
Aircraft	849	Propulsion	Jet aircraft use airbreathing jet engines, which take in air, burn fuel with it in a combustion chamber, and accelerate the exhaust rearwards to provide thrust.
Aircraft	849	Propulsion	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 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.
Aircraft	849	Propulsion	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.
Aircraft	849	Propulsion	Some rotorcraft, such as helicopters, have 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	849	Design and construction	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 the design process is regulated by national airworthiness authorities.
Aircraft	849	Design and construction	The key parts of an aircraft are generally divided into three categories:
Aircraft	849	Design and construction	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 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.
Aircraft	849	Design and construction	The key structural parts of an aircraft depend on what type it is.
Aircraft	849	Design and construction	Lighter-than-air types are characterised by one or more gasbags, typically with 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.
Aircraft	849	Design and construction	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 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.
Aircraft	849	Design and construction	The source of motive power for an aircraft 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).
Aircraft	849	Design and construction	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).
Aircraft	849	Design and construction	The avionics comprise any electronic aircraft flight control systems and related equipment, including electronic cockpit instrumentation, navigation, radar, monitoring, and communications systems.
Aircraft	849	Flight characteristics	The flight envelope of an aircraft refers to its approved design capabilities in terms of airspeed, load factor and altitude. The term can also refer to other assessments of aircraft performance such as maneuverability. When an aircraft is abused, for instance by diving it at too-high a speed, it is said to be flown outside the envelope, something considered foolhardy since it has been taken beyond the design limits which have been established by the manufacturer. Going beyond the envelope may have a known outcome such as flutter or entry to a non-recoverable spin (possible reasons for the boundary).
Aircraft	849	Flight characteristics	The range is the distance an aircraft can fly between takeoff and landing, as limited by the time it can remain airborne.
Aircraft	849	Flight characteristics	For a powered aircraft the time limit is determined by the fuel load and rate of consumption.
Aircraft	849	Flight characteristics	For an unpowered aircraft, the maximum flight time is limited by factors such as weather conditions and pilot endurance. Many aircraft types are restricted to daylight hours, while balloons are limited by their supply of lifting gas. The range can be seen as the average ground speed multiplied by the maximum time in the air.
Aircraft	849	Flight characteristics	The Airbus A350-900ULR is now the longest range airliner.
Aircraft	849	Flight characteristics	Flight dynamics is the science of air vehicle orientation and control in three dimensions. The three critical flight dynamics parameters are the angles of rotation around three axes which pass through the vehicle's center of gravity, known as pitch, roll, and yaw.
Aircraft	849	Flight characteristics	Flight dynamics is concerned with the stability and control of an aircraft's rotation about each of these axes.
Aircraft	849	Flight characteristics	An aircraft that is unstable tends to diverge from its intended flight path and so is difficult to fly. A very stable aircraft tends to stay on its flight path and is difficult to maneuver. Therefore, it is important for any design to achieve the desired degree of stability. Since the widespread use of digital computers, it is increasingly common for designs to be inherently unstable and rely on computerised control systems to provide artificial stability.
Aircraft	849	Flight characteristics	A fixed wing is typically unstable in pitch, roll, and yaw. Pitch and yaw stabilities of conventional fixed wing designs require horizontal and vertical stabilisers, which act similarly to the feathers on an arrow. These stabilizing surfaces allow equilibrium of aerodynamic forces and to stabilise the flight dynamics of pitch and yaw. They are usually mounted on the tail section (empennage), although in the canard layout, the main aft wing replaces the canard foreplane as pitch stabilizer. Tandem wing and tailless aircraft rely on the same general rule to achieve stability, the aft surface being the stabilising one.
Aircraft	849	Flight characteristics	A rotary wing is typically unstable in yaw, requiring a vertical stabiliser.
Aircraft	849	Flight characteristics	A balloon is typically very stable in pitch and roll due to the way the payload is slung underneath the center of lift.
Aircraft	849	Flight characteristics	Flight control surfaces enable the pilot to control an aircraft's flight attitude and are usually part of the wing or mounted on, or integral with, the associated stabilizing surface. Their development was a critical advance in the history of aircraft, which had until that point been uncontrollable in flight.
Aircraft	849	Flight characteristics	Aerospace engineers develop control systems for a vehicle's orientation (attitude) about its center of mass. The control systems include actuators, which exert forces in various directions, and generate rotational forces or moments about the aerodynamic center of the aircraft, and thus rotate the aircraft in pitch, roll, or yaw. For example, a pitching moment is a vertical force applied at a distance forward or aft from the aerodynamic center of the aircraft, causing the aircraft to pitch up or down. Control systems are also sometimes used to increase or decrease drag, for example to slow the aircraft to a safe speed for landing.
Aircraft	849	Flight characteristics	The two main aerodynamic forces acting on any aircraft are lift supporting it in the air and drag opposing its motion. Control surfaces or other techniques may also be used to affect these forces directly, without inducing any rotation.
Aircraft	849	Environmental impact	Aircraft permit long distance, high speed travel and may be a more fuel efficient mode of transportation in some circumstances. Aircraft have environmental and climate impacts beyond fuel efficiency considerations, however. They are also relatively noisy compared to other forms of travel and high altitude aircraft generate contrails, which experimental evidence suggests may alter weather patterns.
Aircraft	849	Uses for aircraft	Aircraft are produced in several different types optimized for various uses; military aircraft, which includes not just combat types but many types of supporting aircraft, and civil aircraft, which include all non-military types, experimental and model.
Aircraft	849	Uses for aircraft	A military aircraft is any aircraft that is operated by a legal or insurrectionary armed service of any type. Military aircraft can be either combat or non-combat:
Aircraft	849	Uses for aircraft	Most military aircraft are powered heavier-than-air types. Other types, such as gliders and balloons, have also been used as military aircraft; for example, balloons were used for observation during the American Civil War and World War I, and military gliders were used during World War II to land troops.
Aircraft	849	Uses for aircraft	Civil aircraft divide into commercial and general types, however there are some overlaps.
Aircraft	849	Uses for aircraft	Commercial aircraft include types designed for scheduled and charter airline flights, carrying passengers, mail and other cargo. The larger passenger-carrying types are the airliners, the largest of which are wide-body aircraft. Some of the smaller types are also used in general aviation, and some of the larger types are used as VIP aircraft.
Aircraft	849	Uses for aircraft	General aviation is a catch-all covering other kinds of private (where the pilot is not paid for time or expenses) and commercial use, and involving a wide range of aircraft types such as business jets (bizjets), trainers, homebuilt, gliders, warbirds and hot air balloons to name a few. The vast majority of aircraft today are general aviation types.
Aircraft	849	Uses for aircraft	An experimental aircraft is one that has not been fully proven in flight, or that carries a Special Airworthiness Certificate, called an Experimental Certificate in United States parlance. This often implies that the aircraft is testing new aerospace technologies, though the term also refers to amateur-built and kit-built aircraft, many of which are based on proven designs.
Aircraft	849	Uses for aircraft	A model aircraft is a small unmanned type made to fly for fun, for static display, for aerodynamic research or for other purposes. A scale model is a replica of some larger design.
Alfred Nobel	851		Alfred Bernhard Nobel (/noʊˈbɛl/ noh-BEL, Swedish: [ˈǎlfrɛd nʊˈbɛlː] ; 21 October 1833 – 10 December 1896) was a Swedish chemist, inventor, engineer and businessman. He is known for inventing dynamite as well as having bequeathed his fortune to establish the Nobel Prize. He also made several important contributions to science, holding 355 patents in his lifetime. Nobel's most famous invention was dynamite, an explosive using nitroglycerin; it was patented in 1867.
Alfred Nobel	851		Nobel displayed an early aptitude for science and learning, particularly in chemistry and languages; he became fluent in six languages and filed his first patent at the age of 24. He embarked on many business ventures with his family, most notably owning the company Bofors, which was an iron and steel producer that he had developed into a major manufacturer of cannons and other armaments.
Alfred Nobel	851		Nobel was later inspired to donate his fortune to the Nobel Prize institution, which would annually recognize those who "conferred the greatest benefit to humankind". The synthetic element nobelium was named after him, and his name and legacy also survives in companies such as Dynamit Nobel and AkzoNobel, which descend from mergers with companies he founded.
Alfred Nobel	851		Nobel was elected a member of the Royal Swedish Academy of Sciences, which, pursuant to his will, would be responsible for choosing the Nobel laureates in physics and in chemistry.
Alfred Nobel	851	Personal life	Alfred Nobel was born in Stockholm, United Kingdoms of Sweden and Norway on 21 October 1833. He was the third son of Immanuel Nobel (1801–1872), an inventor and engineer, and Karolina Andriette Nobel (née Ahlsell 1805–1889). The couple married in 1827 and had eight children. The family was impoverished and only Alfred and his three brothers survived beyond childhood. Through his father, Alfred Nobel was a descendant of the Swedish scientist Olaus Rudbeck (1630–1702), and in his turn, the boy was interested in engineering, particularly explosives, learning the basic principles from his father at a young age. Alfred Nobel's interest in technology was inherited from his father, an alumnus of Royal Institute of Technology in Stockholm.
Alfred Nobel	851	Personal life	Following various business failures caused by the loss of some barges of building material, Immanuel Nobel was forced into bankruptcy, Nobel's father moved to Saint Petersburg, Russia, and grew successful there as a manufacturer of machine tools and explosives. He invented the veneer lathe (which made possible the production of modern plywood) and started work on the torpedo. In 1842, the family joined him in the city. Now prosperous, his parents were able to send Nobel to private tutors, and the boy excelled in his studies, particularly in chemistry and languages, achieving fluency in English, French, German, and Russian. For 18 months, from 1841 to 1842, Nobel went to the only school he ever attended as a child, in Stockholm.
Alfred Nobel	851	Personal life	Nobel gained proficiency in Swedish, French, Russian, English, German, and Italian. He also developed sufficient literary skill to write poetry in English. His Nemesis is a prose tragedy in four acts about the Italian noblewoman Beatrice Cenci. It was printed while he was dying, but the entire stock was destroyed immediately after his death except for three copies, being regarded as scandalous and blasphemous. It was published in Sweden in 2003 and has been translated into Slovenian, French, Italian, and Spanish.
Alfred Nobel	851	Personal life	Nobel was Lutheran and regularly attended the Church of Sweden Abroad during his Paris years, led by pastor Nathan Söderblom who received the Nobel Peace Prize in 1930. He was an agnostic in youth and became an atheist later in life, though he still donated generously to the Church.
Alfred Nobel	851	Personal life	Nobel traveled for much of his business life, maintaining companies in Europe and America while keeping a home in Paris from 1873 to 1891. He remained a solitary character, given to periods of depression. He remained unmarried, although his biographers note that he had at least three loves, the first in Russia with a girl named Alexandra who rejected his proposal. In 1876, Austro-Bohemian Countess Bertha Kinsky became his secretary, but she left him after a brief stay to marry her previous lover Baron Arthur Gundaccar von Suttner. Her contact with Nobel was brief, yet she corresponded with him until his death in 1896, and probably influenced his decision to include a peace prize in his will. She was awarded the 1905 Nobel Peace prize "for her sincere peace activities". Nobel's longest-lasting relationship was with Sofija Hess from Celje whom he met in 1876 in Baden near Vienna, where she worked as an employee in a flower shop. The liaison lasted for 18 years.
Alfred Nobel	851	Personal life	In the years of 1865 to 1873, Alfred Nobel had his home in Krümmel, that now lies in the municipality of Geesthacht, near Hamburg, he afterward moved to a house in the Avenue Malakoff in Paris that same year.
Alfred Nobel	851	Personal life	In 1894, when he acquired Bofors-Gullspång, the Björkborn Manor was included, he stayed at his manor house in Sweden during the summers. The manor house became his very last residence in Sweden and has after his death functioned as a museum.
Alfred Nobel	851	Personal life	Alfred Nobel died on 10 December 1896, in Sanremo, Italy, at his very last residence, Villa Nobel, overlooking the Mediterranean Sea.
Alfred Nobel	851	Scientific career	As a young man, Nobel studied with chemist Nikolai Zinin; then, in 1850, went to Paris to further the work. There he met Ascanio Sobrero, who had invented nitroglycerin three years before. Sobrero strongly opposed the use of nitroglycerin because it was unpredictable, exploding when subjected to variable heat or pressure. But Nobel became interested in finding a way to control and use nitroglycerin as a commercially usable explosive; it had much more power than gunpowder. In 1851 at age 18, he went to the United States for one year to study, working for a short period under Swedish-American inventor John Ericsson, who designed the American Civil War ironclad, USS Monitor. Nobel filed his first patent, an English patent for a gas meter, in 1857, while his first Swedish patent, which he received in 1863, was on "ways to prepare gunpowder".
Alfred Nobel	851	Scientific career	The family factory produced armaments for the Crimean War (1853–1856), but had difficulty switching back to regular domestic production when the fighting ended and they filed for bankruptcy. In 1859, Nobel's father left his factory in the care of the second son, Ludvig Nobel (1831–1888), who greatly improved the business. Nobel and his parents returned to Sweden from Russia and Nobel devoted himself to the study of explosives, and especially to the safe manufacture and use of nitroglycerin. Nobel invented a detonator in 1863, and in 1865 designed the blasting cap.
Alfred Nobel	851	Scientific career	On 3 September 1864, a shed used for preparation of nitroglycerin exploded at the factory in Heleneborg, Stockholm, Sweden, killing five people, including Nobel's younger brother Emil. Fazed by the accident, Nobel founded the company Nitroglycerin AB in Vinterviken so that he could continue to work in a more isolated area. Nobel invented dynamite in 1867, a substance easier and safer to handle than the more unstable nitroglycerin. Dynamite was patented in the US and the UK and was used extensively in mining and the building of transport networks internationally. In 1875, Nobel invented gelignite, more stable and powerful than dynamite, and in 1887, patented ballistite, a predecessor of cordite.
Alfred Nobel	851	Scientific career	Nobel was elected a member of the Royal Swedish Academy of Sciences in 1884, the same institution that would later select laureates for two of the Nobel prizes, and he received an honorary doctorate from Uppsala University in 1893.
Alfred Nobel	851	Scientific career	Nobel's brothers Ludvig and Robert founded the oil company Branobel and became hugely rich in their own right. Nobel invested in these and amassed great wealth through the development of these new oil regions. It operated mainly in Baku, Azerbaijan, but also in Cheleken, Turkmenistan. During his life, Nobel was issued 355 patents internationally, and by his death, his business had established more than 90 armaments factories, despite his apparently pacifist character.
Alfred Nobel	851	Inventions	Nobel found that when nitroglycerin was incorporated in an absorbent inert substance like kieselguhr (diatomaceous earth) it became safer and more convenient to handle, and this mixture he patented in 1867 as "dynamite". Nobel demonstrated his explosive for the first time that year, at a quarry in Redhill, Surrey, England. In order to help reestablish his name and improve the image of his business from the earlier controversies associated with dangerous explosives, Nobel had also considered naming the highly powerful substance "Nobel's Safety Powder", but settled with Dynamite instead, referring to the Greek word for "power" (δύναμις).
Alfred Nobel	851	Inventions	Nobel later combined nitroglycerin with various nitrocellulose compounds, similar to collodion, but settled on a more efficient recipe combining another nitrate explosive, and obtained a transparent, jelly-like substance, which was a more powerful explosive than dynamite. Gelignite, or blasting gelatin, as it was named, was patented in 1876; and was followed by a host of similar combinations, modified by the addition of potassium nitrate and various other substances. Gelignite was more stable, transportable and conveniently formed to fit into bored holes, like those used in drilling and mining, than the previously used compounds. It was adopted as the standard technology for mining in the "Age of Engineering", bringing Nobel a great amount of financial success, though at a cost to his health. An offshoot of this research resulted in Nobel's invention of ballistite, the precursor of many modern smokeless powder explosives and still used as a rocket propellant.
Alfred Nobel	851	Nobel Prize	There is a well known story about the origin of the Nobel Prize, although historians have been unable to verify it and some dismiss the story as a myth. In 1888, the death of his brother Ludvig supposedly caused several newspapers to publish obituaries of Alfred in error. One French newspaper condemned him for his invention of military explosives—in many versions of the story, dynamite is quoted, although this was mainly used for civilian applications—and this is said to have brought about his decision to leave a better legacy after his death. The obituary stated, Le marchand de la mort est mort ("The merchant of death is dead"), and went on to say, "Dr. Alfred Nobel, who became rich by finding ways to kill more people faster than ever before, died yesterday." Nobel read the obituary and was appalled at the idea that he would be remembered in this way. His decision to posthumously donate the majority of his wealth to found the Nobel Prize has been credited to him wanting to leave behind a better legacy. However, it has been questioned whether or not the obituary in question actually existed.
Alfred Nobel	851	Nobel Prize	On 27 November 1895, at the Swedish-Norwegian Club in Paris, Nobel signed his last will and testament and set aside the bulk of his estate to establish the Nobel Prizes, to be awarded annually without distinction of nationality. After taxes and bequests to individuals, Nobel's will allocated 94% of his total assets, 31,225,000 Swedish kronor, to establish the five Nobel Prizes. This converted to £1,687,837 (GBP) at the time. In 2012, the capital was worth around SEK 3.1 billion (US$472 million, EUR 337 million), which is almost twice the amount of the initial capital, taking inflation into account.
Alfred Nobel	851	Nobel Prize	The first three of these prizes are awarded for eminence in physical science, in chemistry and in medical science or physiology; the fourth is for literary work "in an ideal direction" and the fifth prize is to be given to the person or society that renders the greatest service to the cause of international fraternity, in the suppression or reduction of standing armies, or in the establishment or furtherance of peace congresses.
Alfred Nobel	851	Nobel Prize	The formulation for the literary prize being given for a work "in an ideal direction" (i idealisk riktning in Swedish), is cryptic and has caused much confusion. For many years, the Swedish Academy interpreted "ideal" as "idealistic" (idealistisk) and used it as a reason not to give the prize to important but less romantic authors, such as Henrik Ibsen and Leo Tolstoy. This interpretation has since been revised, and the prize has been awarded to, for example, Dario Fo and José Saramago, who do not belong to the camp of literary idealism.
Alfred Nobel	851	Nobel Prize	There was room for interpretation by the bodies he had named for deciding on the physical sciences and chemistry prizes, given that he had not consulted them before making the will. In his one-page testament, he stipulated that the money go to discoveries or inventions in the physical sciences and to discoveries or improvements in chemistry. He had opened the door to technological awards, but had not left instructions on how to deal with the distinction between science and technology. Since the deciding bodies he had chosen were more concerned with the former, the prizes went to scientists more often than engineers, technicians or other inventors.
Alfred Nobel	851	Nobel Prize	Sweden's central bank Sveriges Riksbank celebrated its 300th anniversary in 1968 by donating a large sum of money to the Nobel Foundation to be used to set up a sixth prize in the field of economics in honor of Alfred Nobel. In 2001, Alfred Nobel's great-great-nephew, Peter Nobel (born 1931), asked the Bank of Sweden to differentiate its award to economists given "in Alfred Nobel's memory" from the five other awards. This request added to the controversy over whether the Bank of Sweden Prize in Economic Sciences in Memory of Alfred Nobel is actually a legitimate "Nobel Prize".
Alfred Nobel	851	Death	Nobel was accused of high treason against France for selling Ballistite to Italy, so he moved from Paris to Sanremo, Italy, in 1891. On 10 December 1896, he suffered a stroke and was partially paralyzed to where he could speak only his native tongue. Nobel was surrounded by his paid servants at the time of his death who didn't speak his native tongue so he wrote, "how sad it is to be without a friend who could whisper a consoling word and would one day gently close one's eyes." He had left most of his wealth in trust, unbeknownst to his family, in order to fund the Nobel Prize awards. He is buried in Norra begravningsplatsen in Stockholm.
Alfred Nobel	851	Monuments and legacy	The Monument to Alfred Nobel (Russian: Памятник Альфреду Нобелю, 59°57′39″N 30°20′06″E / 59.960787°N 30.334905°E / 59.960787; 30.334905) in Saint Petersburg is located along the Bolshaya Nevka River on Petrogradskaya Embankment. It was dedicated in 1991 to mark the 90th anniversary of the first Nobel Prize presentation. Diplomat Thomas Bertelman and Professor Arkady Melua were initiators of the creation of the monument (1989). Professor A. Melua has provided funds for the establishment of the monument (J.S.Co. "Humanistica", 1990–1991). The abstract metal sculpture was designed by local artists Sergey Alipov and Pavel Shevchenko, and appears to be an explosion or branches of a tree. Petrogradskaya Embankment is the street where Nobel's family lived until 1859.
Alfred Nobel	851	Monuments and legacy	Criticism of Nobel focuses on his leading role in weapons manufacturing and sales, and some question his motives in creating his prizes, suggesting they are intended to improve his reputation.

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An aircraft (pl.: aircraft) is a vehicle that 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.

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The human activity that surrounds aircraft 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.

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History

Flying model craft and stories of manned flight go back many centuries; however, 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:

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Methods of lift

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 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.

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Methods of lift

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).

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Methods of lift

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 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 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" is a powered one.

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Methods of lift

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 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.

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Methods of lift

Heavier-than-air aircraft, such as airplanes, must find some way to push air or gas downwards so that a reaction occurs (by Newton's laws of motion) to push the aircraft upwards. This dynamic movement through the air is the origin of the term. There are two ways to produce dynamic upthrust — aerodynamic lift, and powered lift in the form of engine thrust.

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Methods of lift

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.

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Methods of lift

With powered lift, the aircraft directs its engine thrust vertically downward. V/STOL aircraft, such as 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.

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Methods of lift

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.

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Methods of lift

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.

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Methods of lift

The first heavier-than-air craft capable of controlled free-flight were gliders. A glider designed by George Cayley carried out 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.

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Methods of lift

Besides the method of propulsion (if any), fixed-wing aircraft are in general characterized by their wing configuration. The most important wing characteristics are:

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Methods of lift

A variable geometry aircraft can change its wing configuration during flight.

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Methods of lift

A flying wing has no fuselage, though it may have small blisters or pods. The opposite of this is a lifting body, which has no wings, though it may have small stabilizing and control surfaces.

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Methods of lift

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 is only because they are so underpowered—in fact, the airframe is capable of flying higher.

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Methods of lift

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.

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Methods of lift

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. Some have a tail rotor to counteract the rotation of the main rotor, and to aid directional control.

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Methods of lift

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.

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Methods of lift

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 Bell Boeing V-22 Osprey), tiltwing, tail-sitter, and coleopter aircraft have their rotors/propellers horizontal for vertical flight and vertical for forward flight.

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Size and speed extremes

The smallest aircraft are toys/recreational items, and nano aircraft.

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Size and speed extremes

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 a payload of up to 22,050 lb (10,000 kg).

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Size and speed extremes

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 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.

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Size and speed extremes

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 a greater wingspan (94m/260ft) than any current aircraft and a tail height equal to the tallest (Airbus A380-800 at 24.1m/78ft) — flew only one short hop in the late 1940s and never flew out of ground effect.

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Size and speed extremes

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 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).

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Size and speed extremes

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)

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Size and speed extremes

The fastest recorded powered aircraft flight and fastest recorded aircraft flight of an air-breathing powered aircraft was of the NASA X-43A 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.

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Size and speed extremes

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.

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Size and speed extremes

The fastest manned, air-breathing powered airplane 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.

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Propulsion

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 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.

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Propulsion

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.

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Propulsion

Kites are aircraft that are tethered to the ground or other object (fixed or mobile) that maintains tension in 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.

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Propulsion

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 is stored in tanks, usually in the wings but larger aircraft also have additional fuel tanks in the fuselage.

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Propulsion

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.

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Propulsion

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.

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Propulsion

Jet aircraft use airbreathing jet engines, which take in air, burn fuel with it in a combustion chamber, and accelerate the exhaust rearwards to provide thrust.

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Propulsion

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 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.

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Propulsion

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.

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Propulsion

Some rotorcraft, such as helicopters, have 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.

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Design and construction

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 the design process is regulated by national airworthiness authorities.

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Design and construction

The key parts of an aircraft are generally divided into three categories:

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Design and construction

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 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.

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Design and construction

The key structural parts of an aircraft depend on what type it is.

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Design and construction

Lighter-than-air types are characterised by one or more gasbags, typically with 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.

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Design and construction

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 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.

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Design and construction

The source of motive power for an aircraft 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).

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Design and construction

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).

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Design and construction

The avionics comprise any electronic aircraft flight control systems and related equipment, including electronic cockpit instrumentation, navigation, radar, monitoring, and communications systems.

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Flight characteristics

The flight envelope of an aircraft refers to its approved design capabilities in terms of airspeed, load factor and altitude. The term can also refer to other assessments of aircraft performance such as maneuverability. When an aircraft is abused, for instance by diving it at too-high a speed, it is said to be flown outside the envelope, something considered foolhardy since it has been taken beyond the design limits which have been established by the manufacturer. Going beyond the envelope may have a known outcome such as flutter or entry to a non-recoverable spin (possible reasons for the boundary).

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Flight characteristics

The range is the distance an aircraft can fly between takeoff and landing, as limited by the time it can remain airborne.

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Flight characteristics

For a powered aircraft the time limit is determined by the fuel load and rate of consumption.

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Flight characteristics

For an unpowered aircraft, the maximum flight time is limited by factors such as weather conditions and pilot endurance. Many aircraft types are restricted to daylight hours, while balloons are limited by their supply of lifting gas. The range can be seen as the average ground speed multiplied by the maximum time in the air.

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Flight characteristics

The Airbus A350-900ULR is now the longest range airliner.

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Flight characteristics

Flight dynamics is the science of air vehicle orientation and control in three dimensions. The three critical flight dynamics parameters are the angles of rotation around three axes which pass through the vehicle's center of gravity, known as pitch, roll, and yaw.

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Flight characteristics

Flight dynamics is concerned with the stability and control of an aircraft's rotation about each of these axes.

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Flight characteristics

An aircraft that is unstable tends to diverge from its intended flight path and so is difficult to fly. A very stable aircraft tends to stay on its flight path and is difficult to maneuver. Therefore, it is important for any design to achieve the desired degree of stability. Since the widespread use of digital computers, it is increasingly common for designs to be inherently unstable and rely on computerised control systems to provide artificial stability.

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Flight characteristics

A fixed wing is typically unstable in pitch, roll, and yaw. Pitch and yaw stabilities of conventional fixed wing designs require horizontal and vertical stabilisers, which act similarly to the feathers on an arrow. These stabilizing surfaces allow equilibrium of aerodynamic forces and to stabilise the flight dynamics of pitch and yaw. They are usually mounted on the tail section (empennage), although in the canard layout, the main aft wing replaces the canard foreplane as pitch stabilizer. Tandem wing and tailless aircraft rely on the same general rule to achieve stability, the aft surface being the stabilising one.

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Flight characteristics

A rotary wing is typically unstable in yaw, requiring a vertical stabiliser.

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Flight characteristics

A balloon is typically very stable in pitch and roll due to the way the payload is slung underneath the center of lift.

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Flight characteristics

Flight control surfaces enable the pilot to control an aircraft's flight attitude and are usually part of the wing or mounted on, or integral with, the associated stabilizing surface. Their development was a critical advance in the history of aircraft, which had until that point been uncontrollable in flight.

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Flight characteristics

Aerospace engineers develop control systems for a vehicle's orientation (attitude) about its center of mass. The control systems include actuators, which exert forces in various directions, and generate rotational forces or moments about the aerodynamic center of the aircraft, and thus rotate the aircraft in pitch, roll, or yaw. For example, a pitching moment is a vertical force applied at a distance forward or aft from the aerodynamic center of the aircraft, causing the aircraft to pitch up or down. Control systems are also sometimes used to increase or decrease drag, for example to slow the aircraft to a safe speed for landing.

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Flight characteristics

The two main aerodynamic forces acting on any aircraft are lift supporting it in the air and drag opposing its motion. Control surfaces or other techniques may also be used to affect these forces directly, without inducing any rotation.

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Environmental impact

Aircraft permit long distance, high speed travel and may be a more fuel efficient mode of transportation in some circumstances. Aircraft have environmental and climate impacts beyond fuel efficiency considerations, however. They are also relatively noisy compared to other forms of travel and high altitude aircraft generate contrails, which experimental evidence suggests may alter weather patterns.

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Uses for aircraft

Aircraft are produced in several different types optimized for various uses; military aircraft, which includes not just combat types but many types of supporting aircraft, and civil aircraft, which include all non-military types, experimental and model.

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Uses for aircraft

A military aircraft is any aircraft that is operated by a legal or insurrectionary armed service of any type. Military aircraft can be either combat or non-combat:

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Uses for aircraft

Most military aircraft are powered heavier-than-air types. Other types, such as gliders and balloons, have also been used as military aircraft; for example, balloons were used for observation during the American Civil War and World War I, and military gliders were used during World War II to land troops.

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Uses for aircraft

Civil aircraft divide into commercial and general types, however there are some overlaps.

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Uses for aircraft

Commercial aircraft include types designed for scheduled and charter airline flights, carrying passengers, mail and other cargo. The larger passenger-carrying types are the airliners, the largest of which are wide-body aircraft. Some of the smaller types are also used in general aviation, and some of the larger types are used as VIP aircraft.

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Uses for aircraft

General aviation is a catch-all covering other kinds of private (where the pilot is not paid for time or expenses) and commercial use, and involving a wide range of aircraft types such as business jets (bizjets), trainers, homebuilt, gliders, warbirds and hot air balloons to name a few. The vast majority of aircraft today are general aviation types.

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Uses for aircraft

An experimental aircraft is one that has not been fully proven in flight, or that carries a Special Airworthiness Certificate, called an Experimental Certificate in United States parlance. This often implies that the aircraft is testing new aerospace technologies, though the term also refers to amateur-built and kit-built aircraft, many of which are based on proven designs.

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Uses for aircraft

A model aircraft is a small unmanned type made to fly for fun, for static display, for aerodynamic research or for other purposes. A scale model is a replica of some larger design.

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Alfred Bernhard Nobel (/noʊˈbɛl/ noh-BEL, Swedish: [ˈǎlfrɛd nʊˈbɛlː] ; 21 October 1833 – 10 December 1896) was a Swedish chemist, inventor, engineer and businessman. He is known for inventing dynamite as well as having bequeathed his fortune to establish the Nobel Prize. He also made several important contributions to science, holding 355 patents in his lifetime. Nobel's most famous invention was dynamite, an explosive using nitroglycerin; it was patented in 1867.

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Nobel displayed an early aptitude for science and learning, particularly in chemistry and languages; he became fluent in six languages and filed his first patent at the age of 24. He embarked on many business ventures with his family, most notably owning the company Bofors, which was an iron and steel producer that he had developed into a major manufacturer of cannons and other armaments.

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Nobel was later inspired to donate his fortune to the Nobel Prize institution, which would annually recognize those who "conferred the greatest benefit to humankind". The synthetic element nobelium was named after him, and his name and legacy also survives in companies such as Dynamit Nobel and AkzoNobel, which descend from mergers with companies he founded.

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Nobel was elected a member of the Royal Swedish Academy of Sciences, which, pursuant to his will, would be responsible for choosing the Nobel laureates in physics and in chemistry.

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Personal life

Alfred Nobel was born in Stockholm, United Kingdoms of Sweden and Norway on 21 October 1833. He was the third son of Immanuel Nobel (1801–1872), an inventor and engineer, and Karolina Andriette Nobel (née Ahlsell 1805–1889). The couple married in 1827 and had eight children. The family was impoverished and only Alfred and his three brothers survived beyond childhood. Through his father, Alfred Nobel was a descendant of the Swedish scientist Olaus Rudbeck (1630–1702), and in his turn, the boy was interested in engineering, particularly explosives, learning the basic principles from his father at a young age. Alfred Nobel's interest in technology was inherited from his father, an alumnus of Royal Institute of Technology in Stockholm.

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Personal life

Following various business failures caused by the loss of some barges of building material, Immanuel Nobel was forced into bankruptcy, Nobel's father moved to Saint Petersburg, Russia, and grew successful there as a manufacturer of machine tools and explosives. He invented the veneer lathe (which made possible the production of modern plywood) and started work on the torpedo. In 1842, the family joined him in the city. Now prosperous, his parents were able to send Nobel to private tutors, and the boy excelled in his studies, particularly in chemistry and languages, achieving fluency in English, French, German, and Russian. For 18 months, from 1841 to 1842, Nobel went to the only school he ever attended as a child, in Stockholm.

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Personal life

Nobel gained proficiency in Swedish, French, Russian, English, German, and Italian. He also developed sufficient literary skill to write poetry in English. His Nemesis is a prose tragedy in four acts about the Italian noblewoman Beatrice Cenci. It was printed while he was dying, but the entire stock was destroyed immediately after his death except for three copies, being regarded as scandalous and blasphemous. It was published in Sweden in 2003 and has been translated into Slovenian, French, Italian, and Spanish.

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Personal life

Nobel was Lutheran and regularly attended the Church of Sweden Abroad during his Paris years, led by pastor Nathan Söderblom who received the Nobel Peace Prize in 1930. He was an agnostic in youth and became an atheist later in life, though he still donated generously to the Church.

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Personal life

Nobel traveled for much of his business life, maintaining companies in Europe and America while keeping a home in Paris from 1873 to 1891. He remained a solitary character, given to periods of depression. He remained unmarried, although his biographers note that he had at least three loves, the first in Russia with a girl named Alexandra who rejected his proposal. In 1876, Austro-Bohemian Countess Bertha Kinsky became his secretary, but she left him after a brief stay to marry her previous lover Baron Arthur Gundaccar von Suttner. Her contact with Nobel was brief, yet she corresponded with him until his death in 1896, and probably influenced his decision to include a peace prize in his will. She was awarded the 1905 Nobel Peace prize "for her sincere peace activities". Nobel's longest-lasting relationship was with Sofija Hess from Celje whom he met in 1876 in Baden near Vienna, where she worked as an employee in a flower shop. The liaison lasted for 18 years.

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Personal life

In the years of 1865 to 1873, Alfred Nobel had his home in Krümmel, that now lies in the municipality of Geesthacht, near Hamburg, he afterward moved to a house in the Avenue Malakoff in Paris that same year.

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Personal life

In 1894, when he acquired Bofors-Gullspång, the Björkborn Manor was included, he stayed at his manor house in Sweden during the summers. The manor house became his very last residence in Sweden and has after his death functioned as a museum.

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Personal life

Alfred Nobel died on 10 December 1896, in Sanremo, Italy, at his very last residence, Villa Nobel, overlooking the Mediterranean Sea.

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Scientific career

As a young man, Nobel studied with chemist Nikolai Zinin; then, in 1850, went to Paris to further the work. There he met Ascanio Sobrero, who had invented nitroglycerin three years before. Sobrero strongly opposed the use of nitroglycerin because it was unpredictable, exploding when subjected to variable heat or pressure. But Nobel became interested in finding a way to control and use nitroglycerin as a commercially usable explosive; it had much more power than gunpowder. In 1851 at age 18, he went to the United States for one year to study, working for a short period under Swedish-American inventor John Ericsson, who designed the American Civil War ironclad, USS Monitor. Nobel filed his first patent, an English patent for a gas meter, in 1857, while his first Swedish patent, which he received in 1863, was on "ways to prepare gunpowder".

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Scientific career

The family factory produced armaments for the Crimean War (1853–1856), but had difficulty switching back to regular domestic production when the fighting ended and they filed for bankruptcy. In 1859, Nobel's father left his factory in the care of the second son, Ludvig Nobel (1831–1888), who greatly improved the business. Nobel and his parents returned to Sweden from Russia and Nobel devoted himself to the study of explosives, and especially to the safe manufacture and use of nitroglycerin. Nobel invented a detonator in 1863, and in 1865 designed the blasting cap.

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Scientific career

On 3 September 1864, a shed used for preparation of nitroglycerin exploded at the factory in Heleneborg, Stockholm, Sweden, killing five people, including Nobel's younger brother Emil. Fazed by the accident, Nobel founded the company Nitroglycerin AB in Vinterviken so that he could continue to work in a more isolated area. Nobel invented dynamite in 1867, a substance easier and safer to handle than the more unstable nitroglycerin. Dynamite was patented in the US and the UK and was used extensively in mining and the building of transport networks internationally. In 1875, Nobel invented gelignite, more stable and powerful than dynamite, and in 1887, patented ballistite, a predecessor of cordite.

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Scientific career

Nobel was elected a member of the Royal Swedish Academy of Sciences in 1884, the same institution that would later select laureates for two of the Nobel prizes, and he received an honorary doctorate from Uppsala University in 1893.

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Scientific career

Nobel's brothers Ludvig and Robert founded the oil company Branobel and became hugely rich in their own right. Nobel invested in these and amassed great wealth through the development of these new oil regions. It operated mainly in Baku, Azerbaijan, but also in Cheleken, Turkmenistan. During his life, Nobel was issued 355 patents internationally, and by his death, his business had established more than 90 armaments factories, despite his apparently pacifist character.

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Inventions

Nobel found that when nitroglycerin was incorporated in an absorbent inert substance like kieselguhr (diatomaceous earth) it became safer and more convenient to handle, and this mixture he patented in 1867 as "dynamite". Nobel demonstrated his explosive for the first time that year, at a quarry in Redhill, Surrey, England. In order to help reestablish his name and improve the image of his business from the earlier controversies associated with dangerous explosives, Nobel had also considered naming the highly powerful substance "Nobel's Safety Powder", but settled with Dynamite instead, referring to the Greek word for "power" (δύναμις).

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Inventions

Nobel later combined nitroglycerin with various nitrocellulose compounds, similar to collodion, but settled on a more efficient recipe combining another nitrate explosive, and obtained a transparent, jelly-like substance, which was a more powerful explosive than dynamite. Gelignite, or blasting gelatin, as it was named, was patented in 1876; and was followed by a host of similar combinations, modified by the addition of potassium nitrate and various other substances. Gelignite was more stable, transportable and conveniently formed to fit into bored holes, like those used in drilling and mining, than the previously used compounds. It was adopted as the standard technology for mining in the "Age of Engineering", bringing Nobel a great amount of financial success, though at a cost to his health. An offshoot of this research resulted in Nobel's invention of ballistite, the precursor of many modern smokeless powder explosives and still used as a rocket propellant.

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Nobel Prize

There is a well known story about the origin of the Nobel Prize, although historians have been unable to verify it and some dismiss the story as a myth. In 1888, the death of his brother Ludvig supposedly caused several newspapers to publish obituaries of Alfred in error. One French newspaper condemned him for his invention of military explosives—in many versions of the story, dynamite is quoted, although this was mainly used for civilian applications—and this is said to have brought about his decision to leave a better legacy after his death. The obituary stated, Le marchand de la mort est mort ("The merchant of death is dead"), and went on to say, "Dr. Alfred Nobel, who became rich by finding ways to kill more people faster than ever before, died yesterday." Nobel read the obituary and was appalled at the idea that he would be remembered in this way. His decision to posthumously donate the majority of his wealth to found the Nobel Prize has been credited to him wanting to leave behind a better legacy. However, it has been questioned whether or not the obituary in question actually existed.

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Nobel Prize

On 27 November 1895, at the Swedish-Norwegian Club in Paris, Nobel signed his last will and testament and set aside the bulk of his estate to establish the Nobel Prizes, to be awarded annually without distinction of nationality. After taxes and bequests to individuals, Nobel's will allocated 94% of his total assets, 31,225,000 Swedish kronor, to establish the five Nobel Prizes. This converted to £1,687,837 (GBP) at the time. In 2012, the capital was worth around SEK 3.1 billion (US$472 million, EUR 337 million), which is almost twice the amount of the initial capital, taking inflation into account.

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Nobel Prize

The first three of these prizes are awarded for eminence in physical science, in chemistry and in medical science or physiology; the fourth is for literary work "in an ideal direction" and the fifth prize is to be given to the person or society that renders the greatest service to the cause of international fraternity, in the suppression or reduction of standing armies, or in the establishment or furtherance of peace congresses.

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Nobel Prize

The formulation for the literary prize being given for a work "in an ideal direction" (i idealisk riktning in Swedish), is cryptic and has caused much confusion. For many years, the Swedish Academy interpreted "ideal" as "idealistic" (idealistisk) and used it as a reason not to give the prize to important but less romantic authors, such as Henrik Ibsen and Leo Tolstoy. This interpretation has since been revised, and the prize has been awarded to, for example, Dario Fo and José Saramago, who do not belong to the camp of literary idealism.

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Nobel Prize

There was room for interpretation by the bodies he had named for deciding on the physical sciences and chemistry prizes, given that he had not consulted them before making the will. In his one-page testament, he stipulated that the money go to discoveries or inventions in the physical sciences and to discoveries or improvements in chemistry. He had opened the door to technological awards, but had not left instructions on how to deal with the distinction between science and technology. Since the deciding bodies he had chosen were more concerned with the former, the prizes went to scientists more often than engineers, technicians or other inventors.

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Nobel Prize

Sweden's central bank Sveriges Riksbank celebrated its 300th anniversary in 1968 by donating a large sum of money to the Nobel Foundation to be used to set up a sixth prize in the field of economics in honor of Alfred Nobel. In 2001, Alfred Nobel's great-great-nephew, Peter Nobel (born 1931), asked the Bank of Sweden to differentiate its award to economists given "in Alfred Nobel's memory" from the five other awards. This request added to the controversy over whether the Bank of Sweden Prize in Economic Sciences in Memory of Alfred Nobel is actually a legitimate "Nobel Prize".

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Death

Nobel was accused of high treason against France for selling Ballistite to Italy, so he moved from Paris to Sanremo, Italy, in 1891. On 10 December 1896, he suffered a stroke and was partially paralyzed to where he could speak only his native tongue. Nobel was surrounded by his paid servants at the time of his death who didn't speak his native tongue so he wrote, "how sad it is to be without a friend who could whisper a consoling word and would one day gently close one's eyes." He had left most of his wealth in trust, unbeknownst to his family, in order to fund the Nobel Prize awards. He is buried in Norra begravningsplatsen in Stockholm.

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Monuments and legacy

The Monument to Alfred Nobel (Russian: Памятник Альфреду Нобелю, 59°57′39″N 30°20′06″E / 59.960787°N 30.334905°E / 59.960787; 30.334905) in Saint Petersburg is located along the Bolshaya Nevka River on Petrogradskaya Embankment. It was dedicated in 1991 to mark the 90th anniversary of the first Nobel Prize presentation. Diplomat Thomas Bertelman and Professor Arkady Melua were initiators of the creation of the monument (1989). Professor A. Melua has provided funds for the establishment of the monument (J.S.Co. "Humanistica", 1990–1991). The abstract metal sculpture was designed by local artists Sergey Alipov and Pavel Shevchenko, and appears to be an explosion or branches of a tree. Petrogradskaya Embankment is the street where Nobel's family lived until 1859.

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Monuments and legacy

Criticism of Nobel focuses on his leading role in weapons manufacturing and sales, and some question his motives in creating his prizes, suggesting they are intended to improve his reputation.