Takeoff is the phase of flight in which an aerospace vehicle leaves the ground and becomes airborne. For aircraft traveling vertically, this is known as liftoff .
69-551: For aircraft that take off horizontally, this usually involves starting with a transition from moving along the ground on a runway . For balloons , helicopters and some specialized fixed-wing aircraft ( VTOL aircraft such as the Harrier and the Bell Boeing V22 Osprey ), no runway is needed. For light aircraft , usually full power is used during takeoff. Large transport category (airliner) aircraft may use
138-404: A combustion chamber , and accelerate the exhaust rearwards to provide thrust. Different jet engine configurations include the turbojet and turbofan , sometimes with the addition of an afterburner . Those with no rotating turbomachinery include the pulsejet and ramjet . These mechanically simple engines produce no thrust when stationary, so the aircraft must be launched to flying speed using
207-402: A reduced power for takeoff, where less than full power is applied in order to prolong engine life, reduce maintenance costs and reduce noise emissions. In some emergency cases, the power used can then be increased to increase the aircraft's performance. Before takeoff, the engines, particularly piston engines , are routinely run up at high power to check for engine-related problems. The aircraft
276-530: A rocket is called "rocket launch". Launches for orbital spaceflights , or launches into interplanetary space , are usually from a fixed location on the ground, but may also be from a floating platform such as the San Marco platform , or the Sea Launch launch vessel. Aircraft An aircraft ( pl. : aircraft) is a vehicle that is able to fly by gaining support from the air . It counters
345-560: A catapult, like the V-1 flying bomb , or a rocket, for example. Other engine types include the motorjet and the dual-cycle Pratt & Whitney J58 . Compared to engines using propellers, jet engines can provide much higher thrust, higher speeds and, above about 40,000 ft (12,000 m), greater efficiency. They are also much more fuel-efficient than rockets . As a consequence nearly all large, high-speed or high-altitude aircraft use jet engines. Some rotorcraft, such as helicopters , have
414-638: A greater wingspan (94m/260 ft) than any current aircraft and a tail height equal to the tallest (Airbus A380-800 at 24.1m/78 ft) — flew only one short hop in the late 1940s and never flew out of ground effect . The largest civilian airplanes, apart from the above-noted An-225 and An-124, are the Airbus Beluga cargo transport derivative of the Airbus A300 jet airliner, the Boeing Dreamlifter cargo transport derivative of
483-674: A marginal case. The forerunner of the fixed-wing aircraft is the kite . Whereas a fixed-wing aircraft relies on its forward speed to create airflow over the wings, a kite is tethered to the ground and relies on the wind blowing over its wings to provide lift. Kites were the first kind of aircraft to fly and were invented in China around 500 BC. Much aerodynamic research was done with kites before test aircraft, wind tunnels , and computer modelling programs became available. The first heavier-than-air craft capable of controlled free-flight were gliders . A glider designed by George Cayley carried out
552-794: A maximum loaded weight of 550–700 t (1,210,000–1,540,000 lb), it was also the heaviest aircraft built to date. It could cruise at 500 mph (800 km/h; 430 kn). The aircraft was destroyed during the Russo-Ukrainian War . The largest military airplanes are the Ukrainian Antonov An-124 Ruslan (world's second-largest airplane, also used as a civilian transport), and American Lockheed C-5 Galaxy transport, weighing, loaded, over 380 t (840,000 lb). The 8-engine, piston/propeller Hughes H-4 Hercules "Spruce Goose" — an American World War II wooden flying boat transport with
621-569: A payload of up to 22,050 lb (10,000 kg). The largest aircraft by weight and largest regular fixed-wing aircraft ever built, as of 2016 , was the Antonov An-225 Mriya . That Soviet-built ( Ukrainian SSR ) six-engine transport of the 1980s was 84 m (276 ft) long, with an 88 m (289 ft) wingspan. It holds the world payload record, after transporting 428,834 lb (194,516 kg) of goods, and has flown 100 t (220,000 lb) loads commercially. With
690-588: A powered "tug" aircraft. For a glider to maintain its forward air speed and lift, it must descend in relation to the air (but not necessarily in relation to the ground). Many gliders can "soar", i.e. , gain height from updrafts such as thermal currents. The first practical, controllable example was designed and built by the British scientist and pioneer George Cayley , whom many recognise as the first aeronautical engineer. Common examples of gliders are sailplanes , hang gliders and paragliders . Balloons drift with
759-491: A powered rotary wing or rotor , where the rotor disc can be angled slightly forward so that a proportion of its lift is directed forwards. The rotor may, like a propeller, be powered by a variety of methods such as a piston engine or turbine. Experiments have also used jet nozzles at the rotor blade tips . Aircraft are designed according to many factors such as customer and manufacturer demand, safety protocols and physical and economic constraints. For many types of aircraft
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#1732786668436828-577: A rigid basket or gondola slung below it to carry its payload. Early aircraft, including airships , often employed flexible doped aircraft fabric covering to give a reasonably smooth aeroshell stretched over a rigid frame. Later aircraft employed semi- monocoque techniques, where the skin of the aircraft is stiff enough to share much of the flight loads. In a true monocoque design there is no internal structure left. The key structural parts of an aircraft depend on what type it is. Lighter-than-air types are characterised by one or more gasbags, typically with
897-406: A single-engine or light twin-engine aircraft, the pilot calculates the length of runway required to take off and clear any obstacles, to ensure sufficient runway to use for takeoff. A safety margin can be added to provide the option to stop on the runway in case of a rejected takeoff . In most such aircraft, any engine failure results in a rejected takeoff as a matter of course, since even overrunning
966-663: A specific percentage of the speed of sound. Usually passenger airliners do not fly faster than around 85% of speed of sound, or Mach 0.85. Supersonic aircraft, like the Concorde and military fighters, use the Machmeter as the main speed instrument with the exception of take-offs and landings. Some aircraft also have a taxi speed indicator for use on the ground. Since the IAS often starts at around 74–93 km/h (40–50 kn) (on jet airliners), pilots may need extra help while taxiing
1035-420: A supporting structure of flexible cables or a rigid framework called its hull. Other elements such as engines or a gondola may also be attached to the supporting structure. Heavier-than-air types are characterised by one or more wings and a central fuselage . The fuselage typically also carries a tail or empennage for stability and control, and an undercarriage for takeoff and landing. Engines may be located on
1104-522: Is a lifting body , which has no wings, though it may have small stabilizing and control surfaces. Wing-in-ground-effect vehicles are generally not considered aircraft. They "fly" efficiently close to the surface of the ground or water, like conventional aircraft during takeoff. An example is the Russian ekranoplan nicknamed the " Caspian Sea Monster ". Man-powered aircraft also rely on ground effect to remain airborne with minimal pilot power, but this
1173-437: Is a powered one. A powered, steerable aerostat is called a dirigible . Sometimes this term is applied only to non-rigid balloons, and sometimes dirigible balloon is regarded as the definition of an airship (which may then be rigid or non-rigid). Non-rigid dirigibles are characterized by a moderately aerodynamic gasbag with stabilizing fins at the back. These soon became known as blimps . During World War II , this shape
1242-423: Is an important value for the pilot because it is the indicated speeds which are specified in the aircraft flight manual for such important performance values as the stall speed . These speeds, in true airspeed terms, vary considerably depending upon density altitude . However, at typical civilian operating speeds, the aircraft's aerodynamic structure responds to dynamic pressure alone, and the aircraft will perform
1311-491: Is any system for helping aircraft into the air (as opposed to strictly under its own power). The reason it might be needed is due to the aircraft's weight exceeding the normal maximum takeoff weight , insufficient power, or the available runway length may be insufficient, or a hot and high airfield, or a combination of all four factors. Assisted takeoff is also required for gliders , which do not have an engine and so are unable to take off by themselves. Hence assisted takeoff
1380-508: Is called aeronautics . Crewed aircraft are flown by an onboard pilot , whereas unmanned aerial vehicles may be remotely controlled or self-controlled by onboard computers . Aircraft may be classified by different criteria, such as lift type, aircraft propulsion (if any), usage and others. Flying model craft and stories of manned flight go back many centuries; however, the first manned ascent — and safe descent — in modern times took place by larger hot-air balloons developed in
1449-404: Is less dense than the surrounding air. When the weight of the lifting gas is added to the weight of the aircraft itself, it is same or less than the mass of the air that the craft displaces. Small hot-air balloons, called sky lanterns , were first invented in ancient China prior to the 3rd century BC and used primarily in cultural celebrations, and were only the second type of aircraft to fly,
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#17327866684361518-564: Is necessary to convert IAS to TAS and/or ground speed (GS) using the following method: With the advent of Doppler radar navigation and, more recently, GPS receivers, with other advanced navigation equipment that allows pilots to read ground speed directly, the TAS calculation in-flight is becoming unnecessary for the purposes of navigation estimations. TAS is the primary method to determine aircraft's cruise performance in manufacturer's specs, speed comparisons and pilot reports. From IAS,
1587-1087: Is normally called the powerplant , and includes engine or motor , propeller or rotor , (if any), jet nozzles and thrust reversers (if any), and accessories essential to the functioning of the engine or motor (e.g.: starter , ignition system , intake system , exhaust system , fuel system , lubrication system, engine cooling system , and engine controls ). Powered aircraft are typically powered by internal combustion engines ( piston or turbine ) burning fossil fuels —typically gasoline ( avgas ) or jet fuel . A very few are powered by rocket power , ramjet propulsion, or by electric motors , or by internal combustion engines of other types, or using other fuels. A very few have been powered, for short flights, by human muscle energy (e.g.: Gossamer Condor ). The avionics comprise any electronic aircraft flight control systems and related equipment, including electronic cockpit instrumentation, navigation, radar , monitoring, and communications systems . Indicated airspeed Indicated airspeed ( IAS )
1656-452: Is not the actual speed through the air even when the aircraft is at sea level under International Standard Atmosphere conditions (15 °C, 1013 hPa , 0% humidity). The IAS needs to be corrected for known instrument and position errors to show true airspeed under those specific atmospheric conditions, and this is the CAS (Calibrated Airspeed). Despite this the pilot's primary airspeed reference,
1725-452: Is only because they are so underpowered—in fact, the airframe is capable of flying higher. Rotorcraft, or rotary-wing aircraft, use a spinning rotor with aerofoil cross-section blades (a rotary wing ) to provide lift. Types include helicopters , autogyros , and various hybrids such as gyrodynes and compound rotorcraft. Helicopters have a rotor turned by an engine-driven shaft. The rotor pushes air downward to create lift. By tilting
1794-465: Is permitted to accelerate to rotation speed (often referred to as V r ). The term rotation is used because the aircraft pivots around the axis of its main landing gear while still on the ground, usually because of gentle manipulation of the flight controls to make or facilitate this change in aircraft attitude (once proper air displacement occurs under / over the wings, an aircraft will lift off on its own; controls are to ease that in). The nose
1863-520: Is raised to a nominal 5 ° –15° nose up pitch attitude to increase lift from the wings and effect liftoff. For most aircraft, attempting a takeoff without a pitch-up would require cruise speeds while still on the runway. Fixed-wing aircraft designed for high-speed operation (such as commercial jet aircraft ) have difficulty generating enough lift at the low speeds encountered during takeoff. These are therefore fitted with high-lift devices , often including slats and usually flaps , which increase
1932-608: Is required. Vertical takeoff refers to aircraft or rockets that take off in a vertical trajectory . Vertical takeoff eliminates the need for airfields. Most vertical take off aircraft are also able to land horizontally, but there were certain rocket-powered aircraft of the Luftwaffe that only took off vertically, landing in other ways. The Bachem Ba 349 Natter landed under a parachute after having taken off vertically. Other late projects developed in Nazi Germany , such as
2001-623: Is stored in tanks, usually in the wings but larger aircraft also have additional fuel tanks in the fuselage . Propeller aircraft use one or more propellers (airscrews) to create thrust in a forward direction. The propeller is usually mounted in front of the power source in tractor configuration but can be mounted behind in pusher configuration . Variations of propeller layout include contra-rotating propellers and ducted fans . Many kinds of power plant have been used to drive propellers. Early airships used man power or steam engines . The more practical internal combustion piston engine
2070-475: Is the Lockheed SR-71 Blackbird , a U.S. reconnaissance jet fixed-wing aircraft, having reached 3,530 km/h (2,193 mph) on 28 July 1976. Gliders are heavier-than-air aircraft that do not employ propulsion once airborne. Take-off may be by launching forward and downward from a high location, or by pulling into the air on a tow-line, either by a ground-based winch or vehicle, or by
2139-523: Is the airspeed of an aircraft as measured by its pitot-static system and displayed by the airspeed indicator (ASI). This is the pilots' primary airspeed reference. This value is not corrected for installation error, instrument error , or the actual encountered air density , being instead calibrated to always reflect the adiabatic compressible flow of the International Standard Atmosphere at sea level. It uses
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2208-650: Is the pilot's primary airspeed reference when operating below transonic or supersonic speeds. Indicated airspeed measured by pitot-tube can be approximately expressed by the following equation delivered from Bernoulli's equation . NOTE: The above equation applies only to conditions that can be treated as incompressible. Liquids are treated as incompressible under almost all conditions. Gases under certain conditions can be approximated as incompressible. See Compressibility . The compression effects can be corrected by use of Poisson constant . This compensation corresponds to equivalent airspeed (EAS) . where: The IAS
2277-629: The Bell Boeing V-22 Osprey ), tiltwing , tail-sitter , and coleopter aircraft have their rotors/ propellers horizontal for vertical flight and vertical for forward flight. The smallest aircraft are toys/recreational items, and nano aircraft . The largest aircraft by dimensions and volume (as of 2016) is the 302 ft (92 m) long British Airlander 10 , a hybrid blimp, with helicopter and fixed-wing features, and reportedly capable of speeds up to 90 mph (140 km/h; 78 kn), and an airborne endurance of two weeks with
2346-693: The Boeing 747 jet airliner/transport (the 747-200B was, at its creation in the 1960s, the heaviest aircraft ever built, with a maximum weight of over 400 t (880,000 lb)), and the double-decker Airbus A380 "super-jumbo" jet airliner (the world's largest passenger airliner). The fastest fixed-wing aircraft and fastest glider, is the Space Shuttle , which re-entered the atmosphere at nearly Mach 25 or 17,500 mph (28,200 km/h) The fastest recorded powered aircraft flight and fastest recorded aircraft flight of an air-breathing powered aircraft
2415-583: The Harrier jump jet and Lockheed Martin F-35B take off and land vertically using powered lift and transfer to aerodynamic lift in steady flight. A pure rocket is not usually regarded as an aerodyne because its flight does not depend on interaction with the air at all (and thus can even fly in the vacuum of outer space ); however, many aerodynamic lift vehicles have been powered or assisted by rocket motors. Rocket-powered missiles that obtain aerodynamic lift at very high speed due to airflow over their bodies are
2484-754: The Heinkel P.1077 Julia or the Focke-Wulf Volksjäger 2 , climbed to their ceiling at a nearly vertical angle and landed later on a skid. Vertical take-off and landing ( VTOL ) aircraft include fixed-wing aircraft that can hover, take off and land vertically as well as helicopters and other aircraft with powered rotors, such as tiltrotors . Some VTOL aircraft can operate in other modes as well, such as CTOL (conventional take-off and landing), STOL (short take-off and landing), and/or STOVL (short take-off and vertical landing). Others, such as some helicopters, can only operate by VTOL, due to
2553-490: The camber and often area of the wing, making it more effective at low speed, thus creating more lift. These are deployed from the wing before takeoff, and retracted during the climb. They can also be deployed at other times, such as before landing. The takeoff speed required varies with aircraft weight and aircraft configuration (flap or slat position, as applicable), and is provided to the flight crew as indicated airspeed . Operations with transport category aircraft employ
2622-420: The 18th century. Each of the two World Wars led to great technical advances. Consequently, the history of aircraft can be divided into five eras: Lighter-than-air aircraft or aerostats use buoyancy to float in the air in much the same way that ships float on the water. They are characterized by one or more large cells or canopies, filled with a lifting gas such as helium , hydrogen or hot air , which
2691-435: The 1930s, large intercontinental flying boats were also sometimes referred to as "ships of the air" or "flying-ships". — though none had yet been built. The advent of powered balloons, called dirigible balloons, and later of rigid hulls allowing a great increase in size, began to change the way these words were used. Huge powered aerostats, characterized by a rigid outer framework and separate aerodynamic skin surrounding
2760-450: The ASI, shows IAS (by definition). The relationship between CAS and IAS is known and documented for each aircraft type and model. The aircraft's pilot manual usually gives critical V speeds as IAS, those speeds indicated by the airspeed indicator. This is because the aircraft behaves similarly at the same IAS no matter what the TAS is: E.g. A pilot landing at a hot and high airfield will use
2829-461: The actual speed that the aircraft uses compared to the ground. This is usually connected to a GPS or similar system. Ground speed is just a pilot aid to estimate if the flight is on time, behind or ahead of schedule. It is not used for takeoff and landing purposes, since the imperative speed for a flying aircraft always is the speed against the wind. The Machmeter is, on subsonic aircraft, a warning indicator. Subsonic aircraft must not fly faster than
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2898-433: The aircraft changes altitude, IAS varies considerably from true airspeed (TAS), the relative velocity between the aircraft and the surrounding air mass. Calibrated airspeed (CAS) is the IAS corrected for instrument and position error . An aircraft's indicated airspeed in knots is typically abbreviated KIAS for " Knots -Indicated Air Speed" (vs. KCAS for calibrated airspeed and KTAS for true airspeed ). The IAS
2967-485: The aircraft lacking landing gear that can handle horizontal motion. VTOL is a subset of V/STOL (vertical and/or short take-off and landing). Besides the helicopter, there are two types of VTOL aircraft in military service: craft using a tiltrotor , such as the Bell Boeing V-22 Osprey , and some aircraft using directed jet thrust such as the Harrier family . The takeoff phase of the flight of
3036-429: The aircraft will gain the most altitude in the least amount of time. Generally speaking, V x is a lower speed than V y , and requires a higher pitch attitude to achieve. The speeds needed for takeoff are relative to the motion of the air ( indicated airspeed ). A headwind will reduce the ground speed needed for takeoff, as there is a greater flow of air over the wings. Typical takeoff air speeds for jetliners are in
3105-470: The aircraft's weight. There are two ways to produce dynamic upthrust — aerodynamic lift by having air flowing past an aerofoil (such dynamic interaction of aerofoils with air is the origin of the term "aerodyne"), or powered lift in the form of reactional lift from downward engine thrust . Aerodynamic lift involving wings is the most common, and can be achieved via two methods. Fixed-wing aircraft ( airplanes and gliders ) achieve airflow past
3174-501: The autogyro moves forward, air blows upward across the rotor, making it spin. This spinning increases the speed of airflow over the rotor, to provide lift. Rotor kites are unpowered autogyros, which are towed to give them forward speed or tethered to a static anchor in high-wind for kited flight. Compound rotorcraft have wings that provide some or all of the lift in forward flight. They are nowadays classified as powered lift types and not as rotorcraft. Tiltrotor aircraft (such as
3243-441: The co-pilot calls V 1 , they will call V R or "rotate," marking speed at which to rotate the aircraft. The V R for transport category aircraft is calculated such as to allow the aircraft to reach the regulatory screen height at V 2 with one engine failed. Then, V 2 (the safe takeoff speed) is called. This speed must be maintained after an engine failure to meet performance targets for rate of climb and angle of climb. In
3312-426: The concept of the takeoff V-speeds : V 1 , V R and V 2 . These speeds are determined not only by the above factors affecting takeoff performance, but also by the length and slope of the runway and any peculiar conditions, such as obstacles off the end of the runway. Below V 1 , in case of critical failures, the takeoff should be aborted; above V 1 the pilot continues the takeoff and returns for landing. After
3381-435: The design process is regulated by national airworthiness authorities. The key parts of an aircraft are generally divided into three categories: The approach to structural design varies widely between different types of aircraft. Some, such as paragliders, comprise only flexible materials that act in tension and rely on aerodynamic pressure to hold their shape. A balloon similarly relies on internal gas pressure, but may have
3450-456: The difference between total pressure and static pressure, provided by the system, to either mechanically or electronically measure dynamic pressure . The dynamic pressure includes terms for both density and airspeed. Since the airspeed indicator cannot know the density, it is by design calibrated to assume the sea level standard atmospheric density when calculating airspeed. Since the actual density will vary considerably from this assumed value as
3519-425: The end of the runway is preferable to lifting off with insufficient power to maintain flight. If an obstacle needs to be cleared, the pilot climbs at the speed for maximum climb angle (V x ), which results in the greatest altitude gain per unit of horizontal distance travelled. If no obstacle needs to be cleared, or after an obstacle is cleared, the pilot can accelerate to the best rate of climb speed (V y ), where
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#17327866684363588-400: The first being kites , which were also first invented in ancient China over two thousand years ago (see Han Dynasty ). A balloon was originally any aerostat, while the term airship was used for large, powered aircraft designs — usually fixed-wing. In 1919, Frederick Handley Page was reported as referring to "ships of the air," with smaller passenger types as "Air yachts." In
3657-532: The first true manned, controlled flight in 1853. The first powered and controllable fixed-wing aircraft (the airplane or aeroplane) was invented by Wilbur and Orville Wright . Besides the method of propulsion (if any), fixed-wing aircraft are in general characterized by their wing configuration . The most important wing characteristics are: A variable geometry aircraft can change its wing configuration during flight. A flying wing has no fuselage, though it may have small blisters or pods. The opposite of this
3726-420: The following speeds can also be calculated: On large jet aircraft the IAS is by far the most important speed indicator. Most aircraft speed limitations are based on IAS, as IAS closely reflects dynamic pressure. TAS is usually displayed as well, but purely for advisory information and generally not in a prominent location. Modern jet airliners also include ground speed (GS) and Machmeter . Ground speed shows
3795-437: The force of gravity by using either static lift or the dynamic lift of an airfoil , or, in a few cases, direct downward thrust from its engines. Common examples of aircraft include airplanes , helicopters , airships (including blimps ), gliders , paramotors , and hot air balloons . The human activity that surrounds aircraft is called aviation . The science of aviation, including designing and building aircraft,
3864-418: The fuselage or wings. On a fixed-wing aircraft the wings are rigidly attached to the fuselage, while on a rotorcraft the wings are attached to a rotating vertical shaft. Smaller designs sometimes use flexible materials for part or all of the structure, held in place either by a rigid frame or by air pressure. The fixed parts of the structure comprise the airframe . The source of motive power for an aircraft
3933-514: The gas bags, were produced, the Zeppelins being the largest and most famous. There were still no fixed-wing aircraft or non-rigid balloons large enough to be called airships, so "airship" came to be synonymous with these aircraft. Then several accidents, such as the Hindenburg disaster in 1937, led to the demise of these airships. Nowadays a "balloon" is an unpowered aerostat and an "airship"
4002-524: The range of 240–285 km/h (130–154 kn ; 149–177 mph ). Light aircraft, such as a Cessna 150 , take off at around 100 km/h (54 kn ; 62 mph ). Ultralights have even lower takeoff speeds. For a given aircraft, the takeoff speed is usually dependent on the aircraft weight; the heavier the weight, the greater the speed needed. Some aircraft are specifically designed for short takeoff and landing (STOL) , which they achieve by becoming airborne at very low speeds. Assisted takeoff
4071-411: The rotor forward, the downward flow is tilted backward, producing thrust for forward flight. Some helicopters have more than one rotor and a few have rotors turned by gas jets at the tips. Some have a tail rotor to counteract the rotation of the main rotor, and to aid directional control. Autogyros have unpowered rotors, with a separate power plant to provide thrust. The rotor is tilted backward. As
4140-405: The same IAS to fly the aircraft at the correct approach and landing speeds as when landing at a cold sea level airfield, even though the TAS must differ considerably between the two landings. Whereas IAS can be reliably used for monitoring critical speeds well below the speed of sound this is not so at higher speeds. An example: Because (1) the compressibility of air changes considerably approaching
4209-462: The same when at the same dynamic pressure. Since it is this same dynamic pressure that drives the airspeed indicator, an aircraft will always, for example, stall at the published indicated airspeed (for the current configuration) regardless of density, altitude or true airspeed. Furthermore, the IAS is specified in some regulations, and by air traffic control when directing pilots, since the airspeed indicator displays that speed (by definition) and it
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#17327866684364278-445: The speed of sound, and (2) the speed of sound varies considerably with temperature and therefore altitude; the maximum speed at which an aircraft structure is safe, the never exceed speed (abbreviated V NE ), is specified at several differing altitudes in faster aircraft's operating manuals, as shown in the sample table below. Ref: Pilot's Notes for Tempest V Sabre IIA Engine - Air Ministry A.P.2458C-PN For navigation, it
4347-530: The tether or kite line ; they rely on virtual or real wind blowing over and under them to generate lift and drag. Kytoons are balloon-kite hybrids that are shaped and tethered to obtain kiting deflections, and can be lighter-than-air, neutrally buoyant, or heavier-than-air. Powered aircraft have one or more onboard sources of mechanical power, typically aircraft engines although rubber and manpower have also been used. Most aircraft engines are either lightweight reciprocating engines or gas turbines . Engine fuel
4416-460: The wind, though normally the pilot can control the altitude, either by heating the air or by releasing ballast, giving some directional control (since the wind direction changes with altitude). A wing-shaped hybrid balloon can glide directionally when rising or falling; but a spherically shaped balloon does not have such directional control. Kites are aircraft that are tethered to the ground or other object (fixed or mobile) that maintains tension in
4485-431: The wing. A flexible wing is a wing made of fabric or thin sheet material, often stretched over a rigid frame, similar to the flight membranes on many flying and gliding animals . A kite is tethered to the ground and relies on the speed of the wind over its wings, which may be flexible or rigid, fixed, or rotary. With powered lift, the aircraft directs its engine thrust vertically downward. V/STOL aircraft, such as
4554-402: The wings by having the entire aircraft moving forward through the air, while rotorcraft ( helicopters and autogyros ) do so by having mobile, elongated wings spinning rapidly around a mast in an assembly known as the rotor . As aerofoils, there must be air flowing over the wing to create pressure difference between above and below, thus generating upward lift over the entire wetted area of
4623-675: Was of the NASA X-43 A Pegasus , a scramjet -powered, hypersonic , lifting body experimental research aircraft, at Mach 9.68 or 6,755 mph (10,870 km/h) on 16 November 2004. Prior to the X-43A, the fastest recorded powered airplane flight, and still the record for the fastest manned powered airplane, was the North American X-15 , rocket-powered airplane at Mach 6.7 or 7,274 km/h (4,520 mph) on 3 October 1967. The fastest manned, air-breathing powered airplane
4692-490: Was used for virtually all fixed-wing aircraft until World War II and is still used in many smaller aircraft. Some types use turbine engines to drive a propeller in the form of a turboprop or propfan . Human-powered flight has been achieved, but has not become a practical means of transport. Unmanned aircraft and models have also used power sources such as electric motors and rubber bands. Jet aircraft use airbreathing jet engines , which take in air, burn fuel with it in
4761-439: Was widely adopted for tethered balloons ; in windy weather, this both reduces the strain on the tether and stabilizes the balloon. The nickname blimp was adopted along with the shape. In modern times, any small dirigible or airship is called a blimp, though a blimp may be unpowered as well as powered. Heavier-than-air aircraft or aerodynes are denser than air and thus must find some way to obtain enough lift that can overcome
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