In aeronautics, a propeller called an airscrew, converts rotary motion from an engine or other power source into a swirling slipstream which pushes the propeller forwards or backwards. It comprises a rotating power-driven hub, to which are attached several radial airfoil-section blades such that the whole assembly rotates about a longitudinal axis; the blade pitch may be fixed, manually variable to a few set positions, or of the automatically-variable "constant-speed" type. The propeller attaches to the power source's driveshaft either directly or through reduction gearing. Propellers can be made from metal or composite materials. Propellers are only suitable for use at subsonic airspeeds below about 480 mph, as above this speed the blade tip speed approaches the speed of sound and local supersonic flow causes high drag and propeller structural problems; 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 between ones hands.
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 other works, it was not until the early 1480s, when 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, man continued to pursue the idea of vertical flight. Many of these models and machines would more resemble the ancient bamboo flying top with spinning wings, rather than Leonardo's screw. 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. A dirigible airship was described by Jean Baptiste Marie Meusnier presented in 1783; the drawings depict a 260-foot-long streamlined envelope with internal ballonets that could be used for regulating lift. The airship was designed to be driven by three propellers. In 1784 Jean-Pierre Blanchard fitted a hand-powered propeller to a balloon, the first recorded means of propulsion carried aloft. 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.
William Bland sent designs for his "Atmotic Airship" to the Great Exhibition held in London in 1851, where a model was displayed. This was an elongated balloon with a steam engine driving twin propellers suspended underneath. Alphonse Pénaud developed coaxial rotor model helicopter toys in 1870 powered by rubber bands. In 1872 Dupuy de Lome launched a large navigable balloon, driven by a large propeller turned by eight men. 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. One of Pénaud's toys, given as a gift by their father, inspired the Wright brothers to pursue the dream of flight; the twisted airfoil shape of an aircraft propeller was pioneered by the Wright Brothers. While some earlier engineers had attempted to model air propellers on marine propellers, the Wright Brothers realized that a propeller is the same as a wing, were able to use data from their earlier wind tunnel experiments on wings, introducing a twist along the length of the blades.
This was necessary to maintain a more uniform angle of attack of the blade along its length. Their original propeller blades had an efficiency of about 82%, compared to 90% for a modern small general aviation propeller, the 3-blade McCauley used on a Bonanza aircraft. Roper quotes 90% for a propeller for a human-powered aircraft. Mahogany was the wood preferred for propellers through World War I, but wartime shortages encouraged use of walnut, oak and ash. Alberto Santos Dumont was another early pioneer, having designed propellers before the Wright Brothers for his airships, he applied the knowledge he gained from experiences with airships to make a propeller with a steel shaft and aluminium blades for his 14 bis biplane in 1906. Some of his designs used a bent aluminium sheet for blades, they were undercambered, this plus the absence of lengthwise twist made them less efficient than the Wright propellers. So, this was the first use of aluminium in the construction of an airscrew. A rotating airfoil behind the aircraft, which pushes it, was called a propeller, while one which pulled from the front was a tractor.
The term'pusher' became adopted for the rear-mounted device in contrast to the tractor configurat
A synchronization gear, or a gun synchronizer, sometimes rather less called an interrupter, is attached to the armament of a single-engine tractor-configuration aircraft so it can fire through the arc of its spinning propeller without bullets striking the blades. The idea presupposes a fixed armament directed by aiming the aircraft in which it is fitted at the target, rather than aiming the gun independently. There are many practical problems arising from the inherently imprecise nature of an automatic gun's firing, the great velocity of the blades of a spinning propeller, the high speed at which any gear synchronizing the two has to operate. Design and experimentation with gun synchronization had been underway in France and Germany in 1913–1914, following the ideas of August Euler, who seems to have been the first to suggest mounting a fixed armament firing in the direction of flight. However, the first practical—if far from reliable—gear to enter operational service was that fitted to the Eindecker monoplane fighters, which entered squadron service with the German Air Service in mid-1915.
The success of the Eindecker led to numerous gun synchronization devices, culminating in the reasonably reliable hydraulic British Constantinesco gear of 1917. By the end of the war German engineers were well on the way to perfecting a gear using an electrical rather than a mechanical or hydraulic link between the engine and the gun, with the gun being triggered by a solenoid rather than by a mechanical "trigger motor". From 1918 to the mid-1930s the standard armament for a fighter aircraft remained two synchronized rifle calibre machine guns, firing forward through the propeller. During the late-1930s, the main role of the fighter was seen as the destruction of large, all-metal bombers, for which the "traditional" light armament was inadequate. Since it was impractical to try to fit more than one or two extra guns in the limited space available in the front of a single-engine aircraft's fuselage, this led to an increasing proportion of the armament being mounted in the wings, firing outside the arc of the propeller.
There were in fact some advantages in dispensing with centrally mounted guns altogether. The conclusive redundancy of synchronization gears did not come until the introduction of jet propulsion and the absence of a propeller for guns to be synchronized with. From the beginnings of practical flight possible military uses for aircraft were considered, although not all writers came to positive conclusions on the subject. By 1913 military exercises in Britain and France had confirmed the usefulness of aircraft for reconnaissance and surveillance, this was seen by a few forward looking officers as implying the need to deter or destroy the enemy's reconnaissance machines, thus aerial combat was by no means unanticipated, the machine gun was from the first seen as the most weapon to be used. "It is that an aircraft, capable of shooting at an enemy machine will have the advantage. The most suitable weapon is a light, air-cooled machine-gun". What was not agreed on was the superiority, at least for an attacking aircraft, of fixed forward-firing guns, aimed by pointing the aircraft at its target, rather than flexible weapons, aimed by a gunner other than the pilot.
"The idea of coupling the firing mechanism to the propeller's rotation is an affectation. The objection is the same as to any gun position, fixed along the longitudinal axis of the aircraft: the pilot is forced to fly directly at the enemy in order to fire. Under certain circumstances this is undesirable"; as late as 1916, pilots of the DH.2 pusher fighter had problems convincing their senior officers that the forward-firing armament of their aircraft was more effective if it was fixed to fire forward rather than being flexible. On the other hand, August Euler had patented the idea of a fixed gun as early as 1910 – long before tractor aircraft became the norm, illustrating his patent with a diagram of a machine gun-armed pusher. A mechanism to enable an automatic weapon to fire between the blades of a whirling propeller is called an interrupter or synchronizer gear. Both these terms are more or less misleading, at least insofar as explaining what happens when the gear functions; the term "interrupter" implies that the gear pauses, or "interrupts" the fire of the gun at the point where one of the blades of the propeller passes in front of its muzzle.
The difficulty is that the slowly revolving propellers of First World War aircraft turned twice or three times for each shot a contemporary machine gun could fire. A two-bladed propeller would therefore obstruct the gun six times every firing cycle of the gun, a four-bladed one twelve times. Another way of putting this is that an "interrupted" gun would have been "blocked" more than forty times every second, while it was firing at a rate in the region of seven rounds per second. Unsurprisingly, the designers of so-called interrupter gears found this too problematic to be attempted, the gaps between "interruptions" would have been too short to allow the gun to fire at all, and yet, "synchronization", in the usual sense of the word, between the rate of fire of a machine gun and the revolutions per minute of a spinning aircraft propeller is a conceptual impossibility. A machine gun fires a constant number of rounds a minute, while this may be boosted by, for instance and increasing the tension on a return spring, or redirecting the gasses produced by each firing, it cannot be varied at w
A strut is a structural component found in engineering, aeronautics and anatomy. Struts work by resisting longitudinal compression, but they may serve in tension. Part of the functionality of the clavicle is to serve as a strut between the scapula and sternum, resisting forces that would otherwise bring the upper limb close to the thorax. Keeping the upper limb away from the thorax is vital for its range of motion. Complete lack of clavicles may be seen in cleidocranial dysostosis, the abnormal proximity of the shoulders to the median plane exemplifies the clavicle's importance as a strut. Strut is a common name in timber framing for a brace of scantlings lighter than a post. Struts are found in roof framing from either a tie beam or a king post to a principal rafter. Struts may be straight or curved. In the U. K. strut is used in a sense of a lighter duty piece: a king post carries a ridge beam but a king strut does not, a queen post carries a plate but a queen strut does not, a crown post carries a crown plate but a crown strut does not.
Strutting or blocking between floor joists adds strength to the floor system. Struts provide outwards-facing support in their lengthwise direction, which can be used to keep two other components separate, performing the opposite function of a tie. In piping, struts restrain movement of a component in one direction while allowing movement or contraction in another direction. Strut channel made from steel, aluminium, or fibre-reinforced plastic is used in the building industry and is used in the support of cable trays and other forms of cable management, pipes support systems. Bracing struts and wires of many kinds were extensively used in early aircraft to stiffen and strengthen, sometimes to form, the main functional airframe. Throughout the 1920s and 1930s they fell out of use in favour of the low-drag cantilever construction. Most aircraft bracing struts are principally loaded in compression, with wires taking the tension loads. Lift struts came into increasing use during the changeover period and remain in use on smaller aircraft today where ultimate performance is not an issue.
They are applied to a high-wing monoplane and act in tension during flight. Struts have been used for purely structural reasons to attach engines, landing gear and other loads; the oil-sprung legs of retractable landing gear are still called Oleo struts. As components of an automobile chassis, struts can be passive braces to reinforce the chassis and/or body, or active components of the suspension. An example of an active unit would be a coilover design in an automotive suspension; the coilover combines a spring in a single unit. A common form of automotive suspension strut in an automobile is the MacPherson strut. MacPherson struts are purchased by the automakers in sets of four completed sub-assemblies: These can be mounted on the car bodies as part of the manufacturers' own assembly operations. A MacPherson strut combines the primary function of a shock absorber, with the ability to support sideways loads not along its axis of compression, somewhat similar to a sliding pillar suspension, thus eliminating the need for an upper suspension arm.
This means that a strut must have a more rugged design, with mounting points near its middle for attachment of such loads. Another type common type of strut used in air suspension is an air strut which combines the shock absorber with an air spring and can be designed in the same fashion as a coilover device; these come available in most types of suspension setups including beam axle and MacPherson strut style design. Transportation-related struts are used in "load bearing" applications ranging from both highway and off-road suspensions to automobile hood and hatch window supports to aircraft wing supports; the majority of struts feature a bearing, but only for the cases, when the strut mounts operate as steering pivots. For such struts, the bearing is the wear item, as it is subject to constant impact of vibration and its condition reflects both wheel alignment and steering response. In vehicle suspension systems, struts are most an assembly of coil-over spring and shock absorber. Other variants to using a coil-over spring as the compressible load bearer include support via pressurized nitrogen gas acting as the spring, rigid support which provides neither longitudinal compression/extension nor damping.
Cabane strut Chapman strut Jury strut Lift strut Spacers and standoffs Strut bar
An aileron is a hinged flight control surface forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in roll, which results in a change in flight path due to the tilting of the lift vector. Movement around this axis is called'rolling' or'banking'; the modern aileron was invented and patented by the British scientist Matthew Piers Watt Boulton in 1868, based on his 1864 paper On Aërial Locomotion. Though there was extensive prior art in the 19th century for the aileron and its functional analog, wing warping, in 1906 the United States granted an expansive patent to the Wright Brothers of Dayton, for the invention of a system of aerodynamic control that manipulated an airplane's control surfaces. Considerable litigation ensued within the United States over the legal issues of lateral roll control, until the First World War compelled the U. S. Government to legislate a legal resolution; the name "aileron", from French, meaning "little wing" refers to the extremities of a bird's wings used to control their flight.
It first appeared in print in the 7th edition of Cassell's French-English Dictionary of 1877, with its lead meaning of "small wing". In the context of powered airplanes it appears in print about 1908. Prior to that, ailerons were referred to as rudders, their older technical sibling, with no distinction between their orientations and functions, or more descriptively as horizontal rudders. Among the earliest printed aeronautical use of'aileron' was that in the French aviation journal L'Aérophile of 1908. Ailerons had more or less supplanted other forms of lateral control, such as wing warping, by about 1915, well after the function of the rudder and elevator flight controls had been standardised. Although there were many conflicting claims over who first invented the aileron and its function, i.e. lateral or roll control, the flight control device was invented and described by the British scientist and metaphysicist Matthew Piers Watt Boulton in his 1864 paper On Aërial Locomotion. He was the first to patent an aileron control system in 1868.
Boulton's description of his lateral flight control system was both complete. It was "the first record we have of appreciation of the necessity for active lateral control as distinguished from.... With this invention of Boulton's we have the birth of the present-day three torque method of airborne control" as was praised by Charles Manly; this was endorsed by C. H. Gibbs-Smith. Boulton's British patent, No. 392 of 1868, issued about 35 years before ailerons were "reinvented" in France, became forgotten and lost from sight until after the flight control device was in general use. Gibbs-Smith stated on several occasions that if the Boulton patent had been revealed at the time of the Wright brothers' legal filings, they might not have been able to claim priority of invention for the lateral control of flying machines; the fact that the Wright brothers were able to gain a patent in 1906 did not invalidate Boulton's lost and forgotten invention. Boulton had described and patented ailerons in 1868 and they were not used on manned aircraft until they were employed on Robert Esnault-Pelterie’s glider in 1904, although in 1871 a French military engineer, Charles Renard and flew an unmanned glider incorporating ailerons on each side, activated by a Boulton-style pendulum controlled single-axis autopilot device.
The pioneering U. S. aeronautical engineer Octave Chanute published descriptions and drawings of the Wright brothers' 1902 glider in the leading aviation periodical of the day, L'Aérophile, in 1903. This prompted Esnault-Pelterie, a French military engineer, to build a Wright-style glider in 1904 that used ailerons in lieu of wing warping; the French journal L’Aérophile published photos of the ailerons on Esnault-Pelterie’s glider which were included in his June 1905 article, its ailerons were copied afterward. The Wright brothers used wing warping instead of ailerons for roll control on their glider in 1902, about 1904 their Flyer II was the only aircraft of its time able to do a coordinated banked turn. During the early years of powered flight the Wrights had better roll control on their designs than airplanes that used movable surfaces. From 1908, as aileron designs were refined it became clear that ailerons were much more effective and practical than wing warping. Ailerons had the advantage of not weakening the airplane's wing structure as did the wing warping technique, one reason for Esnault-Pelterie's decision to switch to ailerons.
By 1911 most biplanes used ailerons rather than wing warping—by 1915 ailerons had become universal on monoplanes as well. The U. S. Government, frustrated by the lack of its country's aeronautical advances in the years leading up to World War I, enforced a patent pool putting an end to the Wright brothers patent war; the Wright company changed its aircraft flight controls from wing warping to the use of ailerons at that time as well. Others who were thought to have been the first to introduce ailerons included: American John J. Montgomery included spring-loaded trailing edge flaps on his second glider: these were operable by the pilot as ailerons. In 1886 his third glider design used rotation of the entire wing rather than just a trailing edge portion for roll control. By his own accounts all of these changes in addition to his use of an elevator for pitch control provided "entire control of the machine in the wind, preventing it from upsetting." New Zealander Richard Pearse reputedly made a power
In aviation, stagger is the relative horizontal fore-aft positioning of stacked wings in a biplane, triplane, or multiplane. An aircraft is said to have positive stagger, or stagger, when the upper wing is positioned forward of the lower wing, Examples include the de Havilland Tiger Moth or Stearman. Conversely, an aeroplane is said to have negative stagger in unusual cases where the upper wing is positioned behind the lower wing, as in the Sopwith Dolphin or Beech Model 17 Staggerwing. An aircraft with the wings positioned directly above each other is said to have unstaggered wings, as in the Sopwith Cuckoo or Vickers Vildebeest; the value sometimes expressed as a distance, s say, but it may be written as a fraction or percentage of the'gap', i.e. s/g. It may be presented as an angle equal to tan−1; the Gloster TSR.38 had a stagger of 0.91 m and a gap of 2.0 m, so the stagger might be written as 0.91 m, 0.455, 45.5% or 24.5°. S is the distance from the leading edge of the upper wing along its chord to the point of intersection of the chord with a line drawn perpendicularly to the chord of the upper wing at the leading edge of the lower wing, all lines being drawn in a plane parallel to the plane of symmetry.
As a general rule, there is a tendency for the upper wing to contribute a greater proportion of the total lift than the lower with positive stagger, less with negative stagger. Increase in positive stagger tends to move the center of pressure forward on the upper wing and backward on the lower wing; when unstaggered, the centers of pressure for upper and lower wings are coincidental. Positive stagger is by far the most common, as this positioning of the upper wing allows better visibility for the crew as well as increased aircraft longitudinal stability, aerodynamic efficiency and maximum lift. Decalage
France the French Republic, is a country whose territory consists of metropolitan France in Western Europe and several overseas regions and territories. The metropolitan area of France extends from the Mediterranean Sea to the English Channel and the North Sea, from the Rhine to the Atlantic Ocean, it is bordered by Belgium and Germany to the northeast and Italy to the east, Andorra and Spain to the south. The overseas territories include French Guiana in South America and several islands in the Atlantic and Indian oceans; the country's 18 integral regions span a combined area of 643,801 square kilometres and a total population of 67.3 million. France, a sovereign state, is a unitary semi-presidential republic with its capital in Paris, the country's largest city and main cultural and commercial centre. Other major urban areas include Lyon, Toulouse, Bordeaux and Nice. During the Iron Age, what is now metropolitan France was inhabited by a Celtic people. Rome annexed the area in 51 BC, holding it until the arrival of Germanic Franks in 476, who formed the Kingdom of Francia.
The Treaty of Verdun of 843 partitioned Francia into Middle Francia and West Francia. West Francia which became the Kingdom of France in 987 emerged as a major European power in the Late Middle Ages following its victory in the Hundred Years' War. During the Renaissance, French culture flourished and a global colonial empire was established, which by the 20th century would become the second largest in the world; the 16th century was dominated by religious civil wars between Protestants. France became Europe's dominant cultural and military power in the 17th century under Louis XIV. In the late 18th century, the French Revolution overthrew the absolute monarchy, established one of modern history's earliest republics, saw the drafting of the Declaration of the Rights of Man and of the Citizen, which expresses the nation's ideals to this day. In the 19th century, Napoleon established the First French Empire, his subsequent Napoleonic Wars shaped the course of continental Europe. Following the collapse of the Empire, France endured a tumultuous succession of governments culminating with the establishment of the French Third Republic in 1870.
France was a major participant in World War I, from which it emerged victorious, was one of the Allies in World War II, but came under occupation by the Axis powers in 1940. Following liberation in 1944, a Fourth Republic was established and dissolved in the course of the Algerian War; the Fifth Republic, led by Charles de Gaulle, remains today. Algeria and nearly all the other colonies became independent in the 1960s and retained close economic and military connections with France. France has long been a global centre of art and philosophy, it hosts the world's fourth-largest number of UNESCO World Heritage Sites and is the leading tourist destination, receiving around 83 million foreign visitors annually. France is a developed country with the world's sixth-largest economy by nominal GDP, tenth-largest by purchasing power parity. In terms of aggregate household wealth, it ranks fourth in the world. France performs well in international rankings of education, health care, life expectancy, human development.
France is considered a great power in global affairs, being one of the five permanent members of the United Nations Security Council with the power to veto and an official nuclear-weapon state. It is a leading member state of the European Union and the Eurozone, a member of the Group of 7, North Atlantic Treaty Organization, Organisation for Economic Co-operation and Development, the World Trade Organization, La Francophonie. Applied to the whole Frankish Empire, the name "France" comes from the Latin "Francia", or "country of the Franks". Modern France is still named today "Francia" in Italian and Spanish, "Frankreich" in German and "Frankrijk" in Dutch, all of which have more or less the same historical meaning. There are various theories as to the origin of the name Frank. Following the precedents of Edward Gibbon and Jacob Grimm, the name of the Franks has been linked with the word frank in English, it has been suggested that the meaning of "free" was adopted because, after the conquest of Gaul, only Franks were free of taxation.
Another theory is that it is derived from the Proto-Germanic word frankon, which translates as javelin or lance as the throwing axe of the Franks was known as a francisca. However, it has been determined that these weapons were named because of their use by the Franks, not the other way around; the oldest traces of human life in what is now France date from 1.8 million years ago. Over the ensuing millennia, Humans were confronted by a harsh and variable climate, marked by several glacial eras. Early hominids led a nomadic hunter-gatherer life. France has a large number of decorated caves from the upper Palaeolithic era, including one of the most famous and best preserved, Lascaux. At the end of the last glacial period, the climate became milder. After strong demographic and agricultural development between the 4th and 3rd millennia, metallurgy appeared at the end of the 3rd millennium working gold and bronze, iron. France has numerous megalithic sites from the Neolithic period, including the exceptiona
A cockpit or flight deck is the area near the front of an aircraft or spacecraft, from which a pilot controls the aircraft. The cockpit of an aircraft contains flight instruments on an instrument panel, the controls that enable the pilot to fly the aircraft. In most airliners, a door separates the cockpit from the aircraft cabin. After the September 11, 2001 attacks, all major airlines fortified their cockpits against access by hijackers; the word cockpit was a sailing term for the coxswain's station in a Royal Navy ship, the location of the ship's rudder controls. Cockpit first appeared in the English language in the 1580s, "a pit for fighting cocks", from cock + pit. Used in nautical sense for midshipmen's compartment below decks. From about 1935, cockpit came to be used informally to refer to the driver's cabin in high performance cars, this is official terminology used to describe the compartment that the driver occupies in a Formula One car. In an airliner, the cockpit is referred to as the flight deck, the term deriving from its use by the RAF for the separate, upper platform in large flying boats where the pilot and co-pilot sat.
In the US and many other countries, the term cockpit is used for airliners. The seat of a powerboat racing craft is referred to as the cockpit; the first airplane with an enclosed cabin appeared in 1912 on the Avro Type F. Military biplanes and the first single-engined fighters and attack aircraft had open cockpits, some as late as the Second World War when enclosed cockpits became the norm; the largest impediment to having closed cabins was the material used to make the windows. Prior to Perspex becoming available in 1933, windows were either safety glass, heavy, or cellulose nitrate, which yellowed and was flammable. In the mid-1920s many aircraft manufacturers began using enclosed cockpits for the first time. Early airplanes with closed cockpits include the 1924 Fokker F. VII, the 1926 German Junkers W 34 transport, the 1926 Ford Trimotor, the 1927 Lockheed Vega, the Spirit of St. Louis and the passenger aircraft manufactured by the Douglas and Boeing companies during the mid-1930s. Open-cockpit airplanes were extinct by the mid-1950s, with the exception of training planes, crop-dusters and homebuilt aircraft designs.
Cockpit windows may be equipped with a sun shield. Most cockpits have windows. Nearly all glass windows in large aircraft have an anti-reflective coating, an internal heating element to melt ice. Smaller aircraft may be equipped with a transparent aircraft canopy. In most cockpits the pilot's control column or joystick is located centrally, although in some military fast jets the side-stick is located on the right hand side. In some commercial airliners both pilots use a side-stick located on the outboard side, so Captain's side-stick on the left and First-officer's seat on the right. Except for some helicopters, the right seat in the cockpit of an aircraft is the seat used by the co-pilot; the captain or pilot in command sits in the left seat, so that they can operate the throttles and other pedestal instruments with his right hand. The tradition has been maintained with the co-pilot on the right hand side; the layout of the cockpit in the military fast jet, has undergone standardisation, both within and between aircraft and nations.
An important development was the "Basic Six" pattern the "Basic T", developed from 1937 onwards by the Royal Air Force, designed to optimise pilot instrument scanning. Ergonomics and Human Factors concerns are important in the design of modern cockpits; the layout and function of cockpit displays controls are designed to increase pilot situation awareness without causing information overload. In the past, many cockpits in fighter aircraft, limited the size of the pilots that could fit into them. Now, cockpits are being designed to accommodate from the 1st percentile female physical size and the 99th percentile male size. In the design of the cockpit in a military fast jet, the traditional "knobs and dials" associated with the cockpit are absent. Instrument panels are now wholly replaced by electronic displays, which are themselves re-configurable to save space. While some hard-wired dedicated switches must still be used for reasons of integrity and safety, many traditional controls are replaced by multi-function re-configurable controls or so-called "soft keys".
Controls are incorporated onto the stick and throttle to enable the pilot to maintain a head-up and eyes-out position – the Hands On Throttle And Stick or HOTAS concept. These controls may be further augmented by control media such as head pointing with a Helmet Mounted Sighting System or Direct voice input. Advances in auditory displays allow for Direct Voice Output of aircraft status information and for the spatial localisation of warning sounds for improved monitoring of aircraft systems; the layout of control panels in modern airliners has become unified across the industry. The majority of the systems-related controls for example, are located in the ceiling on an overhead panel. Radios are placed on a panel between the pilot's seats known as the pedestal. Automatic flight controls such as the autopilot are placed just below the windscreen and above the main instrument panel on the glareshield. A cen