Powered lift or powered-lift refers to a type of aircraft that can take off and land vertically and functions differently from a rotorcraft in horizontal flight. The term is used by the United States Federal Aviation Administration for classification purposes. Powered-lift is one of the seven categories of aircraft designated by the Federal Aviation Administration. Powered-lift means a heavier-than-air aircraft capable of vertical takeoff, vertical landing, low speed flight that depends principally on engine-driven lift devices or engine thrust for lift during these flight regimes and on nonrotating airfoil for lift during horizontal flight; the first powered-lift ratings to be issued by the FAA on a civilian pilot certificate were on 21 August 1997, to pilots of Bell Helicopter and Boeing, of the United States Marine Corps. A convertiplane is an aircraft which uses rotor power for vertical takeoff and landing and converts to fixed-wing lift in normal flight. In tiltrotor and tiltwing designs such as the Bell Boeing V-22 Osprey, the rotor swings forward to act as a propeller in forward flight.
Some designs have a ducted fan design, in which the propeller is surrounded by a large ring-shaped duct to reduce tip losses. The powered rotors of a tiltrotor are mounted on rotating shafts or nacelles at the end of a fixed wing, used for both lift and propulsion. For vertical flight, the rotors are angled to provide thrust upwards, lifting the way a helicopter rotor does; as the aircraft gains speed, the rotors progressively rotate or tilt forward, with the rotors becoming perpendicular to the fuselage of the aircraft, similar to a propeller. In this mode, the wing provides the rotor provides thrust; the wing's greater efficiency helps the tiltrotor achieve higher speeds than helicopters. The Bell Boeing V-22 Osprey by Bell Helicopter and Boeing is a twin-engine tiltrotor design that has two turbine engines each driving three-blade rotors; the rotors function similar to a helicopter in vertical flight, similar to an airplane in forward flight. It first flew on 19 March 1989; the AgustaWestland AW609 tiltrotor is civilian aircraft based on the V-22 Osprey.
The aircraft can land vertically with 2 crew and 9 passengers. The aircraft is expected to be certified in 2017; the tiltwing is similar to the tiltrotor, except that the rotor mountings are fixed to the wing and the whole assembly tilts between vertical and horizontal positions. The Vertol VZ-2 was a research aircraft developed in the late 1950s. Unlike other tiltwing aircraft, Vertol designed the VZ-2 using rotors in place of propellers. On 23 July 1958, the aircraft made its first full transition from vertical flight to horizontal flight. By the time the aircraft was retired in 1965, the VZ-2 had accomplished 450 flights, including 34 full transitions; the Boeing X-50 Dragonfly had a two-bladed rotor driven by the engine for takeoff. In horizontal flight the rotor stopped to act like a wing. Fixed canard and tail surfaces provided lift during transition, stability and control in forward flight. Both examples ended their lives in crashes; the Sikorsky X-Wing had a four-bladed rotor utilizing compressed air to control lift over the surfaces while operating as a helicopter.
At higher forward speeds, the rotor would be stopped to continue providing lift as tandem wings in an X configuration. The program was canceled. A Tail-sitter is an aircraft that rests on the ground pointing vertically upwards, so that it rests on its tail and takes off and lands vertically; the whole aircraft tilts forward horizontally for normal flight. No type has gone into production, although a number of experimental variants have been flown, using both proprotor and jet thrust; some have achieved successful transition between flight modes, as the turboprop-powered Convair XFY Pogo did in November 1954. The coleopter type has an annular wing forming a duct around a lift rotor; the transition to forward flight has never been achieved, although the SNECMA Coléoptère took off and landed vertically on pure jet thrust. The German Focke-Wulf Fw Triebflügel was a design studied during the Second World War, it used pulse jets to power a rotor. Similar to a coleopter fixed-wing aircraft, the Triebflügel was intended to take off and land on its tail, rotating on the pitch axis after takeoff and acceleration for forward flight.
The design was never built beyond model wind tunnel testing. The Harrier Jump Jet covers a series of a military VSTOL jet aircraft, it is capable of vertical/short takeoff and landing and is the only successful design of this type from the many that arose in the 1960s. These aircraft are capable of operating from small spaces, such as fields and aviation-capable ships; the Lockheed F-35B Lightning II is proposed as the next military VSTOL/STOVL design in order to replace the Harrier. A Lift jet is a lightweight jet engine used to provide vertical thrust for VTOL operation, is shut down in forward flight; some VTOL designs have used both vectored thrust from the main engine together with auxiliary lift jets. Lift fan is an aircraft configuration in which lifting fans are located in large holes in an otherwise conventional fixed wing or fuselage, it is used for V/STOL operation. The aircraft takes off using the fans to provide lift transitions to fixed-wing lift in forward flight. Several experimental craft have been flown.
Piasecki Helicopter developed the Piasecki
An attack helicopter is an armed helicopter with the primary role of an attack aircraft, with the capability of engaging targets on the ground, such as enemy infantry and armored fighting vehicles. Due to their heavy armament they are sometimes called helicopter gunships. Weapons used on attack helicopters can include autocannons, machine guns and guided anti-tank missiles such as the Hellfire. Many attack helicopters are capable of carrying air-to-air missiles, though for purposes of self-defense. Today's attack helicopter has two main roles: first, to provide direct and accurate close air support for ground troops, second, the anti-tank role to destroy enemy armor concentrations. Attack helicopters are used to supplement lighter helicopters in the armed scout role. In combat, an attack helicopter is projected to destroy around 17 times its own production cost before it is destroyed. Low-speed, fixed wing Allied aircraft like the Soviet Polikarpov Po-2 training and utility biplane had been used as early as 1942 to provide night harassment attack capability against the Wehrmacht Heer on the Eastern Front, most in the Battle of the Caucasus as exemplified by the Night Witches all-female Soviet air unit.
Following Operation Overlord in 1944, the military version of the slow-flying Piper J-3 Cub high-wing civilian monoplane, the L-4 Grasshopper, begun to be used in a light anti-armor role by a few U. S. Army artillery spotter units over France. During the summer of 1944, U. S. Army Major Charles Carpenter managed to take on an anti-armor role with his rocket-armed Piper L-4, his L-4, bearing US Army serial number 43-30426 and named Rosie the Rocketer, armed with six bazookas, had a notable anti-armor success during an engagement during the Battle of Arracourt on September 20, 1944, employing top attack tactics in knocking out at least four German armored vehicles, as a pioneering example of taking on heavy enemy armor from a slow-flying aircraft. The Germans themselves were engaged in such ad-hoc, low-speed "light aircraft" platforms for ground attack late in the war, with one subtype of the Bücker Bestmann trainer—the Bü 181C-3—armed with four Panzerfaust 100 anti-tank grenade launchers, two under each of the low-winged monoplane's wing panels, for the concluding two months of the war in Europe.
This sort of role, being undertaken by low-speed fixed-wing light aircraft was something, likely to be achievable after World War II, from the increasing numbers of post-war military helicopter designs. The only American helicopter in use during the war years, the Sikorsky R-4, was only being used for rescue and were still much experimental in nature. In the early 1950s, various countries around the world started to make increased use of helicopters in their operations in transport and liaison roles. On it was realised that these helicopters, successors to the World War II-era Sikorsky R-4, could be armed with weapons in order to provide them with limited combat capability. Early examples include armed Sikorsky H-34s in service with the US Air Force and armed Mil Mi-4 in service with the Soviet Air Forces. In the opening months of the Korean War era, in August 1950 a joint US Navy and Marine Corps test used a newly acquired Bell HTL-4 helicopter to test if a bazooka could be fired from a helicopter in flight.
One of the larger 3.5 inch models of the bazooka was chosen, was mounted ahead and to the right of the helicopter to allow the door to remain clear. The bazooka was tested, although it was discovered that it would require shielding for the engine compartment, exposed in the model 47 and other early helicopters; the helicopter itself belonged to a Marine experimental helicopter squadron. This "experimental" trend towards the development of dedicated attack helicopters continued into the 1960s with the deployment of armed Bell UH-1s and Mil Mi-8s during the Vietnam War, to this day the pair of most produced helicopter designs in aviation history; these helicopters proved to be moderately successful in these configurations, but due to a lack of armor protection and speed, they were ineffective platforms for mounting weapons in higher-threat ground combat environments. Since the 1960s, various countries around the world started to design and develop various types of helicopters with the purpose of providing a armed and protected aerial vehicle that can perform a variety of combat roles, from reconnaissance to aerial assault missions.
By the 1990s, the missile-armed attack helicopter evolved into a primary anti-tank weapon. Able to move about the battlefield and launch fleeting "pop-up attacks", helicopters presented a major threat with the presence of organic air defenses; the helicopter gunship became a major tool against tank warfare, most attack helicopters became more and more optimized for the antitank mission. In the mid-1960s, the U. S. Army concluded that a purpose-built attack helicopter with more speed and firepower than current armed helicopters was required in the face of intense ground fire from Viet Cong and NVA troops. Based on this realization, with the growing involvement in Vietnam, the U. S. Army developed the requirements for a dedicated attack helicopter, the Advanced Aerial Fire Support System; the aircraft design selected for this program in 1965, was Lockheed's AH-56 Cheyenne. As the Army began its acquisition of a dedicated attack helicopter, it sought options to improve performance over the continued use of improvised interim aircraft.
Tandem rotor helicopters have two large horizontal rotor assemblies mounted one in front of the other. This configuration is used for large cargo helicopters. Single rotor helicopters need a mechanism to neutralize the yawing movement produced by the single large rotor; this is accomplished by a tail rotor, coaxial rotors, the NOTAR systems. Tandem rotor helicopters, use counter-rotating rotors, with each cancelling out the other's torque. Therefore, all of the power from the engines can be used for lift, whereas a single rotor helicopter uses some of the engine power to counter the torque. An alternative is to mount two rotors in a coaxial configuration; the first successful tandem rotor helicopter was built by Nicolas Florine in 1927. Advantages of the tandem-rotor system are a larger center of gravity range, good longitudinal stability. Disadvantages of the tandem-rotor system are a complex transmission, the need for two large rotors; the two rotors are linked by a transmission that ensures the rotors are synchronized and do not hit each other during an engine failure.
Tandem rotor designs achieve yaw by applying opposite left and right cyclic to each rotor pulling both ends of the helicopter in opposite directions. To achieve pitch, opposite collective is applied to each rotor. Tandem rotor aerodynamics is a complex subject. Tandem rotor helicopters have the advantage of being able to hold more weight with shorter blades, since there are two sets. However, the rear rotor works in the aerodynamic shadow of the front rotor, which reduces its efficiency; this loss can be minimized by increasing the distance between the two rotor hubs, by elevating one hub over the other. Tandem rotor helicopters tend to have a lower disk loading than single rotor helicopters. Tandem rotor helicopters require less power to hover and achieve low speed flight as compared to single rotor helicopters. Both configurations require the same power to achieve high speed flight. HRP Rescuer Piasecki PV-14 HERC Jov-3 Piasecki H-21 McCulloch MC-4 Chu CJC-3/CJC-3A, The Republic Of China prototype helicopter with 190HP engine Piasecki H-25/HUP Retriever Yakovlev Yak-24 Bristol Belvedere Piasecki H-16 Bell HSL Boeing Vertol 107-II CH-46 Sea Knight CH-47 Chinook - most-produced tandem-rotor helicopter Jovair Sedan 4A Filper Helicopter Filper Beta 200 Filper Beta 400 Boeing Vertol XCH-62 Boeing Model 234 Boeing Model 360 Coaxial rotors Intermeshing rotors Rotorcraft Transverse rotors Tiltrotor
A jet engine is a type of reaction engine discharging a fast-moving jet that generates thrust by jet propulsion. This broad definition includes airbreathing jet engines. In general, jet engines are combustion engines. Common parlance applies the term jet engine only to various airbreathing jet engines; these feature a rotating air compressor powered by a turbine, with the leftover power providing thrust via a propelling nozzle – this process is known as the Brayton thermodynamic cycle. Jet aircraft use such engines for long-distance travel. Early jet aircraft used turbojet engines which were inefficient for subsonic flight. Most modern subsonic jet aircraft use more complex high-bypass turbofan engines, they give higher speed and greater fuel efficiency than piston and propeller aeroengines over long distances. A few air-breathing engines made for high speed applications use the ram effect of the vehicle's speed instead of a mechanical compressor; the thrust of a typical jetliner engine went from 5,000 lbf in the 1950s to 115,000 lbf in the 1990s, their reliability went from 40 in-flight shutdowns per 100,000 engine flight hours to less than 1 per 100,000 in the late 1990s.
This, combined with decreased fuel consumption, permitted routine transatlantic flight by twin-engined airliners by the turn of the century, where before a similar journey would have required multiple fuel stops. Jet engines date back to the invention of the aeolipile before the first century AD; this device directed steam power through two nozzles to cause a sphere to spin on its axis. It was seen as a curiosity. Jet propulsion only gained practical applications with the invention of the gunpowder-powered rocket by the Chinese in the 13th century as a type of firework, progressed to propel formidable weaponry. Jet propulsion technology stalled for hundreds of years; the earliest attempts at airbreathing jet engines were hybrid designs in which an external power source first compressed air, mixed with fuel and burned for jet thrust. The Caproni Campini N.1, the Japanese Tsu-11 engine intended to power Ohka kamikaze planes towards the end of World War II were unsuccessful. Before the start of World War II, engineers were beginning to realize that engines driving propellers were approaching limits due to issues related to propeller efficiency, which declined as blade tips approached the speed of sound.
If aircraft performance were to increase beyond such a barrier, a different propulsion mechanism was necessary. This was the motivation behind the development of the gas turbine engine, the commonest form of jet engine; the key to a practical jet engine was the gas turbine, extracting power from the engine itself to drive the compressor. The gas turbine was not a new idea: the patent for a stationary turbine was granted to John Barber in England in 1791; the first gas turbine to run self-sustaining was built in 1903 by Norwegian engineer Ægidius Elling. Such engines did not reach manufacture due to issues of safety, reliability and sustained operation; the first patent for using a gas turbine to power an aircraft was filed in 1921 by Frenchman Maxime Guillaume. His engine was an axial-flow turbojet, but was never constructed, as it would have required considerable advances over the state of the art in compressors. Alan Arnold Griffith published An Aerodynamic Theory of Turbine Design in 1926 leading to experimental work at the RAE.
In 1928, RAF College Cranwell cadet Frank Whittle formally submitted his ideas for a turbojet to his superiors. In October 1929 he developed his ideas further. On 16 January 1930 in England, Whittle submitted his first patent; the patent showed a two-stage axial compressor feeding a single-sided centrifugal compressor. Practical axial compressors were made possible by ideas from A. A. Griffith in a seminal paper in 1926. Whittle would concentrate on the simpler centrifugal compressor only. Whittle was unable to interest the government in his invention, development continued at a slow pace. In 1935 Hans von Ohain started work on a similar design in Germany, both compressor and turbine being radial, on opposite sides of same disc unaware of Whittle's work. Von Ohain's first device was experimental and could run only under external power, but he was able to demonstrate the basic concept. Ohain was introduced to Ernst Heinkel, one of the larger aircraft industrialists of the day, who saw the promise of the design.
Heinkel had purchased the Hirth engine company, Ohain and his master machinist Max Hahn were set up there as a new division of the Hirth company. They had their first HeS 1 centrifugal engine running by September 1937. Unlike Whittle's design, Ohain used hydrogen as fuel, supplied under external pressure, their subsequent designs culminated in the gasoline-fuelled HeS 3 of 5 kN, fitted to Heinkel's simple and compact He 178 airframe and flown by Erich Warsitz in the early morning of August 27, 1939, from Rostock-Marienehe aerodrome, an impressively short time for development. The He 178 was the world's first jet plane. Heinkel applied for a US patent covering the Aircraft Power Plant by Hans Joachim Pabst von Ohain in May 31, 1939. Austrian Anselm Franz of Junkers' engine division introduced the axial-flow compressor in their jet engine. Jumo was assigned the next engine number in the RLM 109-0xx numbering sequence for gas turbine aircraft powerplants, "004", the result was t
A helicopter is a type of rotorcraft in which lift and thrust are supplied by rotors. This allows the helicopter to take off and land vertically, to hover, to fly forward and laterally; these attributes allow helicopters to be used in congested or isolated areas where fixed-wing aircraft and many forms of VTOL aircraft cannot perform. The English word helicopter is adapted from the French word hélicoptère, coined by Gustave Ponton d'Amécourt in 1861, which originates from the Greek helix "helix, whirl, convolution" and pteron "wing". English language nicknames for helicopter include "chopper", "copter", "helo", "heli", "whirlybird". Helicopters were developed and built during the first half-century of flight, with the Focke-Wulf Fw 61 being the first operational helicopter in 1936; some helicopters reached limited production, but it was not until 1942 that a helicopter designed by Igor Sikorsky reached full-scale production, with 131 aircraft built. Though most earlier designs used more than one main rotor, it is the single main rotor with anti-torque tail rotor configuration that has become the most common helicopter configuration.
Tandem rotor helicopters are in widespread use due to their greater payload capacity. Coaxial helicopters, tiltrotor aircraft, compound helicopters are all flying today. Quadcopter helicopters pioneered as early as 1907 in France, other types of multicopter have been developed for specialized applications such as unmanned drones; the earliest references for vertical flight came from China. Since around 400 BC, Chinese children have played with bamboo flying toys; this bamboo-copter is spun by rolling a stick attached to a rotor. The spinning creates lift, the toy flies when released; the 4th-century AD Daoist book Baopuzi by Ge Hong describes some of the ideas inherent to rotary wing aircraft. Designs similar to the Chinese helicopter toy appeared in some Renaissance paintings and other works. In the 18th and early 19th centuries Western scientists developed flying machines based on the Chinese toy, it was not until the early 1480s, when Italian polymath Leonardo da Vinci created a design for a machine that could be described as an "aerial screw", that any recorded advancement was made towards vertical flight.
His notes suggested that he built small flying models, but there were no indications for any provision to stop the rotor from making the craft rotate. As scientific knowledge increased and became more accepted, people continued to pursue the idea of vertical flight. In July 1754, Russian Mikhail Lomonosov had developed a small coaxial modeled after the Chinese top but powered by a wound-up spring device and demonstrated it to the Russian Academy of Sciences, it was powered by a spring, was suggested as a method to lift meteorological instruments. In 1783, Christian de Launoy, his mechanic, used a coaxial version of the Chinese top in a model consisting of contrarotating turkey flight feathers as rotor blades, in 1784, demonstrated it to the French Academy of Sciences. Sir George Cayley, influenced by a childhood fascination with the Chinese flying top, developed a model of feathers, similar to that of Launoy and Bienvenu, but powered by rubber bands. By the end of the century, he had progressed to using sheets of tin for rotor blades and springs for power.
His writings on his experiments and models would become influential on future aviation pioneers. Alphonse Pénaud would develop coaxial rotor model helicopter toys in 1870 powered by rubber bands. One of these toys, given as a gift by their father, would inspire the Wright brothers to pursue the dream of flight. In 1861, the word "helicopter" was coined by Gustave de Ponton d'Amécourt, a French inventor who demonstrated a small steam-powered model. While celebrated as an innovative use of a new metal, the model never lifted off the ground. D'Amecourt's linguistic contribution would survive to describe the vertical flight he had envisioned. Steam power was popular with other inventors as well. In 1878 the Italian Enrico Forlanini's unmanned vehicle powered by a steam engine, rose to a height of 12 meters, where it hovered for some 20 seconds after a vertical take-off. Emmanuel Dieuaide's steam-powered design featured counter-rotating rotors powered through a hose from a boiler on the ground. In 1887 Parisian inventor, Gustave built and flew a tethered electric model helicopter.
In July 1901, the maiden flight of Hermann Ganswindt's helicopter took place in Berlin-Schöneberg. A movie covering the event was taken by Max Skladanowsky. In 1885, Thomas Edison was given US$1,000 by James Gordon Bennett, Jr. to conduct experiments towards developing flight. Edison built a helicopter and used the paper for a stock ticker to create guncotton, with which he attempted to power an internal combustion engine; the helicopter was damaged by explosions and one of his workers was badly burned. Edison reported that it would take a motor with a ratio of three to four pounds per horsepower produced to be successful, based on his experiments. Ján Bahýľ, a Slovak inventor, adapted the internal combustion engine to power his helicopter model that reached a height of 0.5 meters in 1901. On 5 May 1905, his helicopter flew for over 1,500 meters. In 1908, Edison patented his own design for a helicopter powered by a gasoline engine with box kites attached to a mast by cables for a rotor, but it never flew.
In 1906, two French brothers and Louis Breguet, began experimenting with airfoils for helicopters. In
Lockheed F-104 Starfighter
The Lockheed F-104 Starfighter is a single-engine, supersonic interceptor aircraft which became used as an attack aircraft. It was developed by Lockheed for the United States Air Force, but was produced by several other nations, seeing widespread service outside the United States. One of the Century Series of fighter aircraft, it was operated by the air forces of more than a dozen nations from 1958 to 2004, its design team was led by Kelly Johnson, who contributed to the development of the Lockheed P-38 Lightning, Lockheed U-2, Lockheed SR-71 Blackbird, other Lockheed aircraft. The F-104 set numerous world records, including altitude records, its success was marred by the Lockheed bribery scandals, in which Lockheed had given bribes to a considerable number of political and military figures in various nations to influence their judgment and secure several purchase contracts. The poor safety record of the Starfighter brought the aircraft into the public eye in German Air Force service. Fighter ace Erich Hartmann was forced to retire from the Luftwaffe due to his outspoken opposition to selection of the F-104.
The final production version of the fighter model was the F-104S, an all-weather interceptor designed by Aeritalia for the Italian Air Force, equipped with radar-guided AIM-7 Sparrow missiles. An advanced F-104 with a high-mounted wing, known as the CL-1200 Lancer, was considered, but did not proceed past the mock-up stage. Clarence "Kelly" Johnson, the chief engineer at Lockheed's Skunk Works, visited Korea in December 1951 and spoke with fighter pilots about what sort of aircraft they wanted. At the time, the U. S. pilots were confronting the MiG-15 with North American F-86 Sabres, many felt that the MiGs were superior to the larger and more complex American design. The pilots requested a simple aircraft with excellent performance. Armed with this information, Johnson started the design of such an aircraft on his return to the United States. In March, his team was assembled. To achieve the desired performance, Lockheed chose a minimalist approach - a design that would achieve high performance by wrapping the lightest, most aerodynamically efficient airframe possible around a single powerful engine.
The engine chosen was the new General Electric J79 turbojet, an engine of improved performance in comparison with contemporary designs. The small L-246 design powered by a single J79 remained identical to the L-083 Starfighter as delivered; the design was presented to the Air Force in November 1952, they were interested enough to create a General Operating Requirement for a lightweight fighter to replace the North American F-100. Three additional companies replied to the requirement: Republic Aviation with the AP-55, an improved version of its prototype XF-91 Thunderceptor. Although all were interesting, Lockheed had what proved to be an insurmountable lead, was granted a development contract in March 1953 for two prototypes. Work progressed with a mock-up ready for inspection at the end of April, work starting on two prototypes late in May. Meanwhile, the J79 engine was not ready; the first prototype was completed by early 1954 and first flew on 4 March at Edwards AFB. The total time from contract to first flight was less than a year.
When the USAF revealed the existence of the XF-104, they only gave a vague description of it. A drawing in the August 1954 edition of Popular Mechanics was close to the actual design; the prototype had hopped into the air on 18 February, but, not counted as a first flight. On the first official flight, it experienced landing gear retraction problems; the second prototype was destroyed a few weeks during gun-firing trials, but in November 1955, the XF-104 was accepted by the USAF. Based on the XF-104 testing and evaluations, the next variant, the YF-104A, was lengthened and fitted with a General Electric J79 engine, modified landing gear, modified air intakes; the first YF-104A flew on 17 February 1956, with the other 16 trial aircraft, were soon carrying out aircraft and equipment evaluation and tests. Modifications were made to the aircraft including airframe adding a ventral fin. Problems were encountered with the J79 afterburner. On 28 January 1958, the first F-104A to enter service was delivered to the 83rd Fighter Intercepter Wing.
A total of 2,578 F-104s was produced under license by various foreign manufacturers. The F-104 featured a radical wing design. Most jet fighters of the period used a swept-wing or delta-wing design, which provided a reasonable balance between aerodynamic performance and internal space for fuel and equipment; the Lockheed tests, determined that the most efficient shape for high-speed supersonic flight was a small, mid-mounted, trapezoidal wing. The new wing design was thin, with a thickness-to-chord ratio of only 3.36% and an aspect ratio of 2.45. The wing's leading edges were so thin that they presented a cut hazard to ground crews: protective guards had to be installed on the edges during ground operations maintenance; the thinness of the wings re
A fixed-wing aircraft is a flying machine, such as an airplane or aeroplane, capable of flight using wings that generate lift caused by the aircraft's forward airspeed and the shape of the wings. Fixed-wing aircraft are distinct from rotary-wing aircraft, ornithopters; the wings of a fixed-wing aircraft are not rigid. Gliding fixed-wing aircraft, including free-flying gliders of various kinds and tethered kites, can use moving air to gain altitude. Powered fixed-wing aircraft that gain forward thrust from an engine include powered paragliders, powered hang gliders and some ground effect vehicles. Most fixed-wing aircraft are flown by a pilot on board the craft, but some are designed to be unmanned and controlled either remotely or autonomously. Kites were used 2,800 years ago in China, where materials ideal for kite building were available; some authors hold that leaf kites were being flown much earlier in what is now Sulawesi, based on their interpretation of cave paintings on Muna Island off Sulawesi.
By at least 549 AD paper kites were being flown, as it was recorded in that year a paper kite was used as a message for a rescue mission. Ancient and medieval Chinese sources list other uses of kites for measuring distances, testing the wind, lifting men and communication for military operations. Stories of kites were brought to Europe by Marco Polo towards the end of the 13th century, kites were brought back by sailors from Japan and Malaysia in the 16th and 17th centuries. Although they were regarded as mere curiosities, by the 18th and 19th centuries kites were being used as vehicles for scientific research. Around 400 BC in Greece, Archytas was reputed to have designed and built the first artificial, self-propelled flying device, a bird-shaped model propelled by a jet of what was steam, said to have flown some 200 m; this machine may have been suspended for its flight. One of the earliest purported attempts with gliders was by the 11th-century monk Eilmer of Malmesbury, which ended in failure.
A 17th-century account states that the 9th-century poet Abbas Ibn Firnas made a similar attempt, though no earlier sources record this event. In 1799, Sir George Cayley set forth the concept of the modern aeroplane as a fixed-wing flying machine with separate systems for lift and control. Cayley was building and flying models of fixed-wing aircraft as early as 1803, he built a successful passenger-carrying glider in 1853. In 1856, Frenchman Jean-Marie Le Bris made the first powered flight, by having his glider "L'Albatros artificiel" pulled by a horse on a beach. In 1884, the American John J. Montgomery made controlled flights in a glider as a part of a series of gliders built between 1883–1886. Other aviators who made similar flights at that time were Otto Lilienthal, Percy Pilcher, protégés of Octave Chanute. In the 1890s, Lawrence Hargrave conducted research on wing structures and developed a box kite that lifted the weight of a man, his box kite designs were adopted. Although he developed a type of rotary aircraft engine, he did not create and fly a powered fixed-wing aircraft.
Sir Hiram Maxim built a craft that weighed 3.5 tons, with a 110-foot wingspan, powered by two 360-horsepower steam engines driving two propellers. In 1894, his machine was tested with overhead rails to prevent it from rising; the test showed. The craft was uncontrollable, which Maxim, it is presumed, because he subsequently abandoned work on it; the Wright brothers' flights in 1903 with their Flyer I are recognized by the Fédération Aéronautique Internationale, the standard setting and record-keeping body for aeronautics, as "the first sustained and controlled heavier-than-air powered flight". By 1905, the Wright Flyer III was capable of controllable, stable flight for substantial periods. In 1906, Brazilian inventor Alberto Santos Dumont designed and piloted an aircraft that set the first world record recognized by the Aéro-Club de France by flying the 14 bis 220 metres in less than 22 seconds; the flight was certified by the FAI. This was the first controlled flight, to be recognised, by a plane able to take off under its own power alone without any auxiliary machine such as a catapult.
The Bleriot VIII design of 1908 was an early aircraft design that had the modern monoplane tractor configuration. It had movable tail surfaces controlling both yaw and pitch, a form of roll control supplied either by wing warping or by ailerons and controlled by its pilot with a joystick and rudder bar, it was an important predecessor of his Bleriot XI Channel-crossing aircraft of the summer of 1909. World War I served as a testbed for the use of the aircraft as a weapon. Aircraft demonstrated their potential as mobile observation platforms proved themselves to be machines of war capable of causing casualties to the enemy; the earliest known aerial victory with a synchronised machine gun-armed fighter aircraft occurred in 1915, by German Luftstreitkräfte Leutnant Kurt Wintgens. Fighter aces appeared. Following WWI, aircraft technology continued to develop. Alcock and Brown crossed the Atlantic non-stop for the first time in 1919; the first commercial flights took place between the United States and Canada in 1919.
The so-called Golden Age of Aviation occurred between the two World War