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| {{Other uses}}
| | Historically persons, mainly women have had a tendency to believe that the 2nd they begin to lift weights, or create progress in the weights they are lifting which they will become muscle-bound plus bulky. This couldn't be farther from the truth. In order to place on fat, whether it be muscle or fat, we should take in more calories than what you're burning.<br><br>Fad diets have been around forever. You can still find several floating around which have been inside existence since the 1950's. Why will we nonetheless find them? Basically, because they may help you shed a limited pounds, whether or not it really is temporary. Fad [http://safedietplansforwomen.com best diet plan] quick do thus considering they commonly just contain about 800-1600 calories. Although most experts agree which fad diets are an insufficient method to lose fat, they do serve a purpose, whether or not it is little. Most of these diets last anywhere from 3 days up to about 2 weeks, with one week being the average. They encourage you to take 1 week off between the diets should you plan on doing it more than when.<br><br>It refuses to matter how small the weight loss is. When it comes to diet plans, in the event you find 1 that offers we a result then you've got a winner. stay with it!<br><br>Family dinner makes a difference. If you all sit down for a meal, it really is much easier to ensure your child is eating healthy. No matter how busy you may be, try to have 1 family meal together each day.<br><br>How are you able to learn more about how lose weight rapidly diets never work and are not the method to forever lose fat? What you need to do to achieve fat loss without being hungry plus without to buy fat loss treatments that never work?<br><br>Most criticism of low carbohydrate dieting is based on the truth that the dieters can get most of their daily calories from meat, dairy plus different significant fat goods. Medical advice is advised before beginning this type of diet.<br><br>One that has severe restrictions on what you are able to eat, or one which knows which you're human and reside in the real planet, and therefore, enables we to cheat a little? |
| [[Image:Stripe-tailed Hummingbird.jpg|thumb|250px|A [[hummingbird]] in flight]]
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| [[Image:Jumping to fly.jpg|thumb|250px|A [[Barn Swallow]] in flight]]
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| '''Flight''' is the process by which an [[object (physics)|object]] [[Motion (physics)|moves]], through an [[atmosphere]] (especially the [[air]]) or beyond it (as in the case of [[spaceflight]]), by generating [[Lift (force)|aerodynamic lift]], [[Air propulsion|propulsive thrust]], [[Lighter than air|aerostatically]] using [[buoyancy]], or by [[ballistics|ballistic]] movement, without direct support from any surface.<!-- surface = ground or water -->
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| Many things fly, from natural aviators such as [[bird]]s, [[bat]]s and [[insect]]s to human inventions such as [[missile]]s, [[aircraft]] such as [[airplane]]s, [[helicopter]]s and [[balloon]]s, to [[rocket]]s such as [[spacecraft]].
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| The engineering aspects of flight are studied in [[aerospace engineering]] which is subdivided into [[aeronautics]], the study of vehicles that travel through the air, and [[astronautics]], the study of vehicles that travel through space, and in [[ballistics]], the study of the flight of projectiles.
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| ==Types of flight==
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| === Buoyant flight===
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| {{main|Aerostat}}
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| [[File:Goodyear-blimp.jpg|thumb|right|A blimp flies because the upward force is equal or greater than the force of gravity.]]
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| Humans have managed to construct lighter than air vehicles that raise off the ground and fly, due to their [[buoyancy]] in air.
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| An '''aerostat''' is a system that remains aloft primarily through the use of [[buoyancy]] to give an aircraft the same overall density as air. Aerostats include [[balloon (aircraft)|free balloons]], [[airship]]s, and [[moored balloon]]s. An aerostat's main structural component is its [[wikt:envelope|envelope]], a lightweight [[skin]] containing a [[lifting gas]]<ref>Walker 2000, p. 541. Quote: the gas-bag of a balloon or airship.</ref><ref>Coulson-Thomas 1976, p. 281. Quote: fabric enclosing gas-bags of airship.</ref> to provide [[buoyancy]], to which other components are attached.
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| Aerostats are so named because they use "aerostatic" lift, a [[buoyant]] force that does not require lateral movement through the surrounding air mass. By contrast, [[Aircraft#Heavier than air .E2.80.93 aerodynes|aerodynes]] primarily use [[aerodynamic]] [[lift (force)|lift]], which requires the lateral movement of at least some part of the [[aircraft]] through the surrounding air mass.
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| ===Aerodynamic flight===
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| ====Unpowered flight versus powered flight====
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| {{main| Unpowered flight}}
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| Some things that fly do not generate propulsive thrust through the air, for example, the [[flying squirrel]]. This is termed [[gliding (flight)|gliding]]. Some other things can exploit rising air to climb such as [[Bird of prey|raptors]] (when gliding) and [[glider (sailplane)|man-made sailplane gliders]]. This is termed [[Lift (soaring)|soaring]]. However most other birds and all [[powered aircraft]] need a source of [[propulsion]] to climb. This is termed powered flight.
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| ====Animal====
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| [[Image:Female mallard flight - natures pics.jpg|thumb|Female [[Mallard]] Duck]]
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| [[Image:Tau Emerald inflight edit.jpg|thumb|Tau Emerald [[dragonfly]]]]
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| [[Image:Kea in Flight MC.jpg|thumb|[[Kea]]]]
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| {{Main|Flying and gliding animals}}
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| The only groups of [[Flying and gliding animals|living things that use powered flight]] are [[bird]]s, [[insect]]s, and [[bat]]s, while many groups have evolved gliding. The extinct [[Pterosaur]]s, an [[Order (biology)|order]] of reptiles contemporaneous with the [[dinosaur]]s, were also very successful flying animals. Each of these groups' [[wing]]s [[evolution|evolved]] [[Convergent evolution|independently]]. The wings of the flying vertebrate groups are all based on the forelimbs, but differ significantly in structure; those of insects are hypothesized to be highly modified versions of structures that form gills in most other groups of [[arthropod]]s.<ref>Averof, Michalis. [http://www.nature.com/nature/journal/v385/n6617/abs/385627a0.html "Evolutionary origin of insect wings from ancestral gills."] ''Nature'', Volume 385, Issue 385, February 1997, pp. 627–630.</ref>
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| [[Bat]]s are the only [[mammal]]s capable of sustaining level flight.<ref>''World Book Student.'' Chicago: World Book. Retrieved: April 29, 2011.</ref> However, there are several [[Flying squirrel|gliding mammals]] which are able to glide from tree to tree using fleshy membranes between their limbs; some can travel hundreds of meters in this way with very little loss in height. [[Flying frog]]s use greatly enlarged webbed feet for a similar purpose, and there are [[Draco blanfordii|flying lizards]] which fold out their mobile ribs into a pair of flat gliding surfaces. [[Chrysopelea|"Flying" snakes]] also use mobile ribs to flatten their body into an aerodynamic shape, with a back and forth motion much the same as they use on the ground.
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| [[Flying fish]] can glide using enlarged wing-like fins, and have been observed soaring for hundreds of meters. It is thought that this ability was chosen by [[natural selection]] because it was an effective means of escape from underwater predators. The longest recorded flight of a flying fish was 45 seconds.<ref name=aa>[http://news.bbc.co.uk/1/hi/sci/tech/7410421.stm "BBC article and video of flying fish."] ''BBC,'' May 20, 2008. Retrieved: May 20, 2008.</ref>
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| Most [[bird]]s fly (''see [[bird flight]]''), with some exceptions. The largest birds, the [[Ostrich]] and the [[Emu]], are earthbound, as were the now-extinct [[Dodo]]s and the [[Phorusrhacids]], which were the dominant predators of South America in the [[Cenozoic]] era. The non-flying [[penguin]]s have wings adapted for use under water and use the same wing movements for swimming that most other birds use for flight.{{citation needed|date=April 2011}} Most small flightless birds are native to small islands, and lead a lifestyle where flight would offer little advantage.
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| Among living animals that fly, the [[Wandering Albatross]] has the greatest wingspan, up to 3.5 meters (11.5 ft); the [[Great Bustard]] has the greatest weight, topping at 21 kilograms (46 pounds).<ref>[http://www.trumpeterswansociety.org/id.htm "Swan Identification."] ''The Trumpeter Swan Society.'' Retrieved: January 3, 2012.</ref>
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| Many [[species]] of [[insect]]s also fly (See [[insect flight]]).
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| ====Mechanical====<!-- This section is linked from [[Anthony Fokker]] -->
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| {{main|Aviation}}
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| [[Image:flight.rob.arp.750pix.jpg|thumb|'''Mechanical flight''': A [[Robinson R22]] Beta [[helicopter]]]]
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| '''Mechanical flight''' is the use of a [[machine]] to fly. These machines include [[aircraft]] such as [[airplane]]s, [[glider aircraft|gliders]], [[helicopter]]s, [[autogyro]]s, [[airship]]s, [[balloon (aircraft)|balloons]], [[ornithopters]] as well as [[spacecraft]]. [[glider aircraft|Gliders]] are capable of unpowered flight. Another form of mechanical flight is para-sailing where a parachute-like object is pulled by a boat. In an airplane, lift is created by the wings; the shape of the wings of the airplane are designed specially for the type of flight desired. There are different types of wings: tempered, semi-tempered, sweptback, rectangular and elliptical. An aircraft wing is sometimes called an [[airfoil]], which is a device that creates lift when air flows across it.
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| =====Supersonic=====
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| {{main|Supersonic speed}}
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| Supersonic flight is flight faster than the [[speed of sound]]. Supersonic flight is associated with the formation of [[shock wave]]s that form a [[sonic boom]] that can be heard from the ground,<ref>Bern, Peter. [http://news.bbc.co.uk/1/hi/talking_point/3207470.stm "Concorde: You asked a pilot."] ''BBC,'' October 23, 2003.</ref> and is frequently startling. This shockwave takes quite a lot of energy to create and this makes supersonic flight generally less efficient than subsonic flight at about 85% of the speed of sound.
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| ===== Hypersonic =====
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| {{main|Hypersonic speed}}
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| Hypersonic flight is very high speed flight where the heat generated by the compression of the air due to the motion through the air causes chemical changes to the air. Hypersonic flight is achieved by reentering spacecraft such as the [[Space Shuttle]] and [[Soyuz spacecraft|Soyuz]].
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| [[Image:ISS after STS-117 in June 2007.jpg|thumb|The [[International Space Station]] in earth [[orbit]]]]
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| ===Ballistic===
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| {{main|Ballistics}}
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| ====Atmospheric====
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| Some things generate little or no lift and move only or mostly under the action of momentum, gravity, air drag and in some cases thrust. This is termed ''ballistic flight''. Examples include [[ball]]s, [[archery|arrows]], [[bullet]]s, [[firework]]s etc.
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| ====Spaceflight====
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| {{main|Spaceflight}}
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| Essentially an extreme form of ballistic flight, '''spaceflight''' is the use of [[space technology]] to achieve the flight of [[spacecraft]] into and through [[outer space]]. Examples include [[ballistic missile]]s, [[orbital spaceflight]] etc.
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| Spaceflight is used in [[space exploration]], and also in commercial activities like [[space tourism]] and [[telecommunications satellite|satellite telecommunications]]. Additional non-commercial uses of spaceflight include [[Space observatory|space observatories]], [[reconnaissance satellite]]s and other [[earth observation satellite]]s.
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| A spaceflight typically begins with a [[rocket]] [[rocket launch|launch]], which provides the initial thrust to overcome the force of [[gravity]] and propels the spacecraft from the surface of the Earth. Once in space, the motion of a spacecraft—both when unpropelled and when under propulsion—is covered by the area of study called [[astrodynamics]]. Some spacecraft remain in space indefinitely, some disintegrate during [[atmospheric reentry]], and others reach a planetary or lunar surface for landing or impact.
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| ==History==
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| Many human cultures have built devices that fly, from the earliest projectiles such as stones and spears,<ref>[http://www.tmth.edu.gr/en/aet/1/14.html "Archytas of Tar entum."] ''Technology Museum of Thessaloniki, Macedonia, Greece/'' Retrieved: May 6, 2012.</ref><ref>[http://automata.co.uk/History%20page.htm "Ancient history."] ''Automata.'' Retrieved:May 6, 2012.</ref> the
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| [[boomerang]] in [[Australia]], the hot air [[Kongming lantern]], and [[kite]]s.
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| ===Aviation===
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| {{main|Aviation history}}
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| [[George Cayley]] studied flight scientifically in the first half of the 19th century,<ref>{{cite web
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| | title = Sir George Cayley
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| | url = http://www.flyingmachines.org/cayl.html
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| | publisher = Flyingmachines.org
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| | accessdate =26 July 2009
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| | quote = Sir George Cayley is one of the most important people in the history of aeronautics. Many consider him the first true scientific aerial investigator and the first person to understand the underlying principles and forces of flight.}}</ref><ref name="ctie">{{cite web
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| | title = The Pioneers: Aviation and Airmodelling
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| | url = http://www.ctie.monash.edu.au/hargrave/cayley.html
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| | publisher =
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| | accessdate =26 July 2009
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| | quote = Sir George Cayley, is sometimes called the 'Father of Aviation'. A pioneer in his field, he is credited with the first major breakthrough in heavier-than-air flight. He was the first to identify the four aerodynamic forces of flight – weight, lift, drag, and thrust – and their relationship and also the first to build a successful human carrying glider.}}</ref><ref>{{cite web
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| | title = U.S Centennial of Flight Commission – Sir George Cayley.
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| | url = http://www.centennialofflight.gov/essay/Prehistory/Cayley/PH2.htm
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| | publisher =
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| | accessdate =10 September 2008
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| | quote = Sir George Cayley, born in 1773, is sometimes called the Father of Aviation. A pioneer in his field, Cayley literally has two great spurts of aeronautical creativity, separated by years during which he did little with the subject. He was the first to identify the four aerodynamic forces of flight – weight, lift, drag, and thrust and their relationship. He was also the first to build a successful human-carrying glider. Cayley described many of the concepts and elements of the modern aeroplane and was the first to understand and explain in engineering terms the concepts of lift and thrust.}}</ref> and in the second half of the 19th century [[Otto Lillienthal]] made over 200 gliding flights and was also one of the first to understand flight scientifically. His work was replicated and extended by the [[Wright brothers]] who made gliding flights and finally the first controlled and extended, manned powered flights.<ref>[http://www.shapell.org/btl.aspx?2972360 "Orville Wright's Personal Letters on Aviation."] ''Shapell Manuscript Foundation'', (Chicago), 2012.</ref>
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| ===Spaceflight===
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| {{main|History of spaceflight}}
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| Spaceflight, particularly [[human spaceflight]] became a reality in the 20th Century following theoretical and practical breakthroughs by [[Konstantin Tsiolkovsky]] and [[Robert H. Goddard]]. The [[Sputnik 1|first orbital spaceflight]] was in 1957<ref>http://history.nasa.gov/sputnik/sputorig.html</ref> and [[Yuri Gagarin]] was carried aboard the first manned orbital spaceflight in 1961.<ref>[http://www.nasa.gov/mission_pages/shuttle/sts1/gagarin_anniversary.html "Gagarin anniversary."] ''NASA''. Retrieved: May 6, 2012.</ref>
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| ==Physics==
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| [[Image:Luftschiff small.jpg|thumb|Lighter-than-air [[airship]]s are able to fly without any major input of energy]]
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| {{main|Aerodynamics}}
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| There are different approaches to flight. If an object has a lower [[density]] than air, then it is [[buoyancy|buoyant]] and is able to [[aerostat|float in the air]] without using energy. A heavier than air craft, known as an [[Aircraft#Heavier than air .E2.80.93 aerodynes|aerodyne]], includes flighted animals and insects, [[fixed-wing aircraft]] and [[rotorcraft]]. Because the craft is heavier than air, it must generate [[lift (force)|lift]] to overcome its [[weight]]. The wind resistance caused by the craft moving through the air is called [[drag (physics)|drag]] and is overcome by [[Air propulsion|propulsive thrust]] except in the case of [[gliding (flight)|gliding]].
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| Some vehicles also use thrust for flight, for example [[rocket]]s and [[Harrier Jump Jet]]s.
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| Finally, [[momentum]] dominates the flight of ballistic flying objects.
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| ===Forces===
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| [[Image:Forces2.gif|thumb|Main forces on a heavier-than-air aircraft]]
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| {{main|Aerodynamics}}
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| Forces relevant to flight are<ref>[http://www.grc.nasa.gov/WWW/K-12/airplane/forces.html "Four forces on an aeroplane."] ''NASA.'' Retrieved: January 3, 2012.</ref>
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| * [[Air propulsion|Propulsive thrust]]: (except in gliders)
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| * [[Lift (force)|Lift]]: created by the reaction to an airflow
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| * [[Drag (physics)|Drag]]: created by aerodynamic [[friction]]
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| * [[Weight]]: (created by gravity)
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| * [[Buoyancy]]: for lighter than air flight
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| These forces must be balanced for stable flight to occur.
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| ====Lift====
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| {{main|lift (force)}}
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| In the context of an [[fluid flow|air flow]] relative to a flying body, the '''lift''' force is the [[Vector (geometric)#Vector components|component]] of the [[aerodynamic force]] that is [[perpendicular]] to the flow direction.<ref>[http://www.lerc.nasa.gov/WWW/K-12/aerosim/Manual/fsim0020.htm "Definition of lift."] ''NASA.'' Retrieved: May 6, 2012.</ref> It contrasts with the [[drag (physics)|drag]] force, which is the [[Parallel (geometry)|parallel]] component of the aerodynamic force. In all cases, aerodynamic lift is associated with pressures on the wing that sum over the area of the flight surfaces to create the lift force, and there is a net movement of air in the opposite direction from the force which is indirectly created by these pressures, in accordance with [[Newton's third law of motion]].
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| Lift is commonly associated with the [[wing]] of an [[Fixed-wing aircraft|aircraft]], although lift is also generated by [[Helicopter rotor|rotors]] on [[rotorcraft]]. While common meanings of the word "[[wikt:lift#English|lift]]" suggest that lift opposes gravity, aerodynamic lift can be in any direction. When an aircraft is in [[cruise (flight)|cruise]] for example, lift does oppose gravity, but occurs at an angle when climbing, descending or banking.
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| Lift can also occur in a different way if the air is not still, especially if there is an updraft due to heat ("thermals") or wind blowing along sloping terrain or other meteorological conditions. This form of lift permits [[Lift (soaring)|soaring]] and is particularly important for gliding. It is used by birds and gliders to stay in the air for long periods with little effort.
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| ====Drag====
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| {{main|Drag (physics)}}
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| For a solid object moving through a fluid, the drag is the component of the [[Net force|net]] [[Aerodynamic force|aerodynamic]] or [[hydrodynamics|hydrodynamic]] [[force]] acting opposite to the direction of the movement.<ref>French 1970, p. 210.</ref><ref>[http://www.ucmp.berkeley.edu/vertebrates/flight/physics.html "Basic flight physics."] ''Berkeley University.'' Retrieved: May 6, 2012.</ref><ref name=NASAdrag>[http://www.grc.nasa.gov/WWW/k-12/airplane/drag1.html "What is Drag?"] ''NASA.'' Retrieved: May 6, 2012.</ref><ref>[http://lorien.ncl.ac.uk/ming/particle/cpe124p2.html "Motions of particles through fluids."] ''lorien.ncl.ac.'' Retrieved: May 6, 2012.</ref> The component perpendicular to this direction is considered [[Lift (force)|lift]]. Therefore drag opposes the motion of the object, and in a powered vehicle it is overcome by [[thrust]].
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| ====Buoyancy====
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| {{main|Buoyancy}}
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| Air pressure acting up against an object in air is greater than the pressure above pushing down. The buoyancy, in both cases, is equal to the weight of fluid displaced - [[Archimedes' principle]] holds for air just as it does for water.
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| A cubic meter of air at ordinary [[atmospheric pressure]] and room temperature has a mass of about 1.2 kilograms, so its weight is about 12 newtons. Therefore, any 1-cubic-meter object in air is buoyed up with a force of 12 newtons. If the mass of the 1-cubic-meter object is greater than 1.2 kilograms (so that its weight is greater than 12 newtons), it falls to the ground when released. If an object of this size has a mass less than 1.2 kilograms, it rises in the air. Any object that has a mass that is less than the mass of an equal volume of air will rise in air - in other words, any object less dense than air will rise.
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| ====Lift-to-drag ratio====
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| [[Image:Drag Curve 2.jpg|thumb|right|Speed and drag relationships for a typical flight article]]
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| {{main|Lift-to-drag ratio}}
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| When lift is created by the motion of an object through the air, this deflects the air, and this is the source of lift. For sustained level flight lift must be equal to weight.
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| However, this lift inevitably causes some drag also, and it turns out that the efficiency of lift creation can be associated with a lift-to-drag ratio for a vehicle; the lift-to-drag ratios are approximately constant over a wide range of speeds.
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| Lift-to-drag ratios can be determined by flight test, by calculation or by testing in a wind tunnel.{{Citation needed|date=May 2012}} Lift-to-drag ratios for practical aircraft vary from about 4:1 up to 60:1 or more. The lower ratios are generally for vehicles and birds with relatively short wings, and the higher ratios are for vehicles with very long wings, such as gliders. In general, long wings permit a large amount of air to be deflected and accelerated by a small amount, rather than a small amount of air by a large amount. Since energy is a square law on deflection speed, whereas lift is a linear relation, it takes less energy, and less [[lift-induced drag]] is created, with longer wings.
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| ====Thrust to weight ratio====
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| {{main|Thrust-to-weight ratio}}
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| '''Thrust-to-weight ratio''' is, as its name suggests, the ratio of instantaneous [[thrust]] to [[weight]] (where weight means weight at the [[Earth]]’s standard acceleration <math>g_0</math>).<ref name="sutton">Sutton and Biblarz 2000, p. 442. Quote: "thrust-to-weight ratio F/W<sub>0</sub> is a dimensionless parameter that is identical to the acceleration of the rocket propulsion system (expressed in multiples of g0) if it could fly by itself in a gravity free vacuum."</ref> It is a dimensionless parameter characteristic of [[rocket]]s and other jet engines and of vehicles propelled by such engines (typically space [[launch vehicle]]s and jet [[aircraft]]).
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| If the [[thrust-to-weight ratio]] is greater than the local gravity strength (expressed in ''g''s), then flight can occur without any forward motion or any aerodynamic lift being required.
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| If the thrust-to-weight ratio times the lift-to-drag ratio is greater than local gravity then [[takeoff]] using aerodynamic lift is possible.
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| ===Flight dynamics===
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| [[Image:Aptch.gif|thumb|right|200px|[[Aircraft principal axes|Pitch]]]]
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| [[Image:Ayaw.gif|thumb|right|200px|[[Yaw (rotation)|Yaw]]]]
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| [[Image:Aileron roll.gif|thumb|right|200px|[[List (watercraft)|List]] or [[Aerobatic maneuver|Roll]]]]
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| [[File:dihedral.airliner.arp.750pix.jpg|thumb|The upward tilt of the wings and tailplane of an aircraft, as seen on this [[Boeing 737]], is called dihedral angle]]{{main|Flight dynamics}}
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| '''Flight dynamics''' is the science of [[aircraft|air]] and [[spacecraft|space]] vehicle orientation and control in three dimensions. The three critical flight dynamics parameters are the angles of rotation in three [[dimensions]] about the vehicle's [[center of mass]], known as ''pitch'', ''roll'' and ''yaw'' (See [[Tait-Bryan rotations]] for an explanation).
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| The control of these dimensions can involve a [[horizontal stabilizer]] (i.e. "a tail"), [[ailerons]] and other movable aerodynamic devices which control angular stability i.e. flight attitude (which in turn affects [[altitude]], [[Aircraft heading|heading]]). Wings are often angled slightly upwards- they have "positive [[Dihedral (aircraft)|dihedral angle]]" which gives inherent roll stabilization.
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| ===Energy efficiency===
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| {{main|propulsive efficiency}}
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| To create thrust so as to be able to gain height, and to push through the air to overcome the drag associated with lift all takes energy. Different objects and creatures capable of flight vary in the efficiency of their muscles, motors and how well this translates into forward thrust.
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| Propulsive efficiency determines how much energy vehicles generate from a unit of fuel.<ref>[http://www.hq.nasa.gov/pao/History/SP-468/ch10-3.htm ch10-3 "History."] ''NASA.'' Retrieved: May 6, 2012.</ref><ref>Honicke et al. 1968 {{Page needed|date=May 2012}}</ref>
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| ===Range===
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| {{main|range (aircraft)}}
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| The range that powered flight articles can achieve is ultimately limited by their drag, as well as how much energy they can store on board.
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| For powered aircraft the useful energy is determined by their [[fuel fraction]]- what percentage of the takeoff weight is fuel, as well as the [[specific energy]] of the fuel used.
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| ===Power-to-weight ratio===
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| {{main|power-to-weight ratio}}
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| All animals and devices capable of sustained flight need relatively high power-to-weight ratios to be able to generate enough lift and/or thrust to achieve take off.
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| ==Takeoff and landing==
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| {{main|takeoff and landing}}
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| Vehicles that can fly can have different ways to '''takeoff and land'''. Conventional aircraft accelerate along the ground until sufficient lift is generated for [[takeoff]], and reverse the process for [[landing]]. Some aircraft can takeoff at low speed, this is called a short takeoff. Some aircraft such as helicopters and Harrier jump jets can takeoff and land vertically. Rockets also usually takeoff and land vertically, but some designs can land horizontally.
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| ==Guidance, Navigation and Control==
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| {{main|Guidance, Navigation and Control}}
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| ===Guidance===
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| {{main|Guidance system}}
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| A '''guidance system''' is a device or group of devices used to [[navigation|navigate]] a [[ship]], [[aircraft]], [[missile]], [[rocket]], [[satellite]], or other craft. Typically, this refers to a system that navigates without direct or continuous human control. Systems that are intended to have a high degree of human interaction are usually referred to as a [[navigation system]].
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| ===Navigation===
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| In aircraft, successful [[air navigation]] involves piloting an aircraft from place to place without getting lost, breaking the laws applying to aircraft, or endangering the safety of those on board or on the [[Earth|ground]].
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| The techniques used for [[navigation]] in the air will depend on whether the aircraft is flying under the [[visual flight rules]] (VFR) or the [[instrument flight rules]] (IFR). In the latter case, the [[aviator|pilot]] will navigate exclusively using [[flight instruments|instruments]] and [[radio navigation aid]]s such as beacons, or as directed under [[radar]] control by [[air traffic control]]. In the VFR case, a pilot will largely navigate using [[dead reckoning]] combined with visual observations (known as [[pilotage]]), with reference to appropriate maps. This may be supplemented using radio navigation aids.
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| ===Control===
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| {{main|Flight control system}}
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| A conventional fixed-wing '''aircraft flight control system''' consists of [[flight control surfaces]], the respective cockpit controls, connecting linkages, and the necessary operating mechanisms to control an aircraft's direction in flight. [[Aircraft engine controls]] are also considered as flight controls as they change speed.
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| ====Traffic====
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| In the case of aircraft, air traffic is controlled by [[air traffic control]] systems.
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| [[Collision avoidance (spacecraft)|Collision avoidance]] is the process of controlling spacecraft to try to prevent collisions.
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| ==Flight safety==
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| {{main|air safety}}
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| '''Air safety''' is a term encompassing the theory, investigation and categorization of [[Aviation accidents and incidents|flight failures]], and the prevention of such failures through regulation, education and training. It can also be applied in the context of campaigns that inform the public as to the safety of [[air travel]].
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| ==See also==
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| {{commons category|Flight}}
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| * [[Aerodynamics]]
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| * [[Levitation]]
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| * [[Transvection (flying)]]
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| ==References==
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| ;Notes
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| {{Reflist|33em}}
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| ;Bibliography
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| {{Refbegin}}
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| * Coulson-Thomas, Colin. ''The Oxford Illustrated Dictionary.'' Oxford, UK: Oxford University Press, 1976, First edition 1975, ISBN 978-0-19-861118-9.
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| * French, A. P. ''Newtonian Mechanics'' (The M.I.T. Introductory Physics Series) (1st ed.). New York: W. W. Norton & Company Inc., 1970.
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| * Honicke, K., R. Lindner, P. Anders, M. Krahl, H. Hadrich and K. Rohricht. ''Beschreibung der Konstruktion der Triebwerksanlagen.'' Berlin: Interflug, 1968.
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| * Sutton, George P. Oscar Biblarz. ''Rocket Propulsion Elements.'' New York: Wiley-Interscience, 2000 (7th edition). ISBN 978-0-471-32642-7.
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| * Walker, Peter. ''[[Chambers Dictionary|Chambers Dictionary of Science and Technology]].'' Edinburgh: Chambers Harrap Publishers Ltd., 2000, First edition 1998. ISBN 978-0-550-14110-1.
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| {{Refend}}
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| ==External links==
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| {{wiktionary|flight}}
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| * [http://www.vega.org.uk/video/programme/84 'Birds in Flight and Aeroplanes' by Evolutionary Biologist and trained Engineer John Maynard-Smith] Freeview video provided by the Vega Science Trust.
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| [[Category:Aerodynamics]]
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| [[Category:Flight| ]]
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