1.
Avionics
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Avionics are the electronic systems used on aircraft, artificial satellites, and spacecraft. Avionic systems include communications, navigation, the display and management of systems. These can be as simple as a searchlight for a helicopter or as complicated as the tactical system for an airborne early warning platform. The term avionics is a portmanteau of the aviation and electronics. The term avionics was coined by the journalist Philip J. Klass as a portmanteau of aviation electronics, many modern avionics have their origins in World War II wartime developments. For example, autopilot systems that are today were started to help bomber planes fly steadily enough to hit precision targets from high altitudes. Famously, radar was developed in the UK, Germany, modern avionics is a substantial portion of military aircraft spending. Aircraft like the F‑15E and the now retired F‑14 have roughly 20 percent of their budget spent on avionics, most modern helicopters now have budget splits of 60/40 in favour of avionics. The civilian market has seen a growth in cost of avionics. Flight control systems and new navigation needs brought on by tighter airspaces, have pushed up development costs, the major change has been the recent boom in consumer flying. As more people begin to use planes as their method of transportation. The majority of power their avionics using 14- or 28‑volt DC electrical systems, however, larger. One source of international standards for equipment are prepared by the Airlines Electronic Engineering Committee. Communications connect the deck to the ground and the flight deck to the passengers. On‑board communications are provided by systems and aircraft intercoms. The VHF aviation communication system works on the airband of 118.000 MHz to 136.975 MHz, each channel is spaced from the adjacent ones by 8.33 kHz in Europe,25 kHz elsewhere. VHF is also used for line of communication such as aircraft-to-aircraft. Amplitude modulation is used, and the conversation is performed in simplex mode, aircraft communication can also take place using HF or satellite communication
2.
Glass cockpit
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A glass cockpit is an aircraft cockpit that features electronic flight instrument displays, typically large LCD screens, rather than the traditional style of analog dials and gauges. This simplifies aircraft operation and navigation and allows pilots to focus only on the most pertinent information and they are also popular with airline companies as they usually eliminate the need for a flight engineer, saving costs. In recent years the technology has become available in small aircraft. As aircraft displays have modernized, the sensors that feed them have modernized as well, traditional gyroscopic flight instruments have been replaced by electronic attitude and heading reference systems and air data computers, improving reliability and reducing cost and maintenance. GPS receivers are usually integrated into glass cockpits, glass cockpits originated in military aircraft in the late 1960s and early 1970s, an early example is the Mark II avionics of the F-111D, which featured a multi-function display. Prior to the 1970s, air operations were not considered sufficiently demanding to require advanced equipment like electronic flight displays. Also, computer technology was not at a level where sufficiently light, the increasing complexity of transport aircraft, the advent of digital systems and the growing air traffic congestion around airports began to change that. The success of the NASA-led glass cockpit work is reflected in the acceptance of electronic flight displays beginning with the introduction of the MD-80 in 1979. Airlines and their passengers alike have benefited, the safety and efficiency of flights have been increased with improved pilot understanding of the aircrafts situation relative to its environment. By the end of the 1990s, liquid-crystal display panels were increasingly favored among aircraft manufacturers because of their efficiency, earlier LCD panels suffered from poor legibility at some viewing angles and poor response times, making them unsuitable for aviation. The glass cockpit has become standard equipment in airliners, business jets and it was fitted into NASAs Space Shuttle orbiters Atlantis, Columbia, Discovery, and Endeavour, and the current Russian Soyuz TMA model spacecraft that was launched in 2002. By the end of the century glass cockpits began appearing in general aviation aircraft as well, in 2003, Cirrus Designs SR20 and SR22 became the first light aircraft equipped with glass cockpits, which they made standard on all Cirrus aircraft. The Lockheed Martin F-35 Lightning II features a panoramic cockpit display touchscreen that replaces most of the switches and toggles found in an aircraft cockpit and they look and behave very similarly to other computers, with windows and data that can be manipulated with point-and-click devices. They also add terrain, approach charts, weather, vertical displays, the improved concepts enable aircraft makers to customize cockpits to a greater degree than previously. All of the manufacturers involved have chosen to do so in one way or another—such as using a trackball, many of the modifications offered by the aircraft manufacturers improve situational awareness and customize the human-machine interface to increase safety. Modern glass cockpits might include Synthetic Vision or Enhanced Vision systems, Enhanced Vision systems add real-time information from external sensors, such as an infrared camera. All new airliners such as the Airbus A380, Boeing 787 and private jets such as Bombardier Global Express, many modern general aviation aircraft are available with glass cockpits. Systems such as the Garmin G1000 are now available on many new GA aircraft, many small aircraft can also be modified post-production to replace analogue instruments
3.
Flight instruments
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Flight instruments are the instruments in the cockpit of an aircraft that provide the pilot with information about the flight situation of that aircraft, such as altitude, airspeed and direction. They improve safety by allowing the pilot to fly the aircraft in level flight, visual flight rules require an airspeed indicator, an altimeter, and a compass or other suitable magnetic direction indicator. Instrument flight rules require a gyroscopic pitch-bank, direction and rate of turn indicator, plus a slip-skid indicator, adjustable altimeter. Flight into Instrument meteorological conditions require radio navigation instruments for precise takeoffs, the term is sometimes used loosely as a synonym for cockpit instruments as a whole, in which context it can include engine instruments, navigational and communication equipment. Many modern aircraft have electronic flight instrument systems, most regulated aircraft have these flight instruments as dictated by the US Code of Federal Regulations, Title 14, Part 91. They are grouped according to system, compass systems. It is adjustable for local barometric pressure which must be set correctly to obtain accurate altitude readings, as the aircraft ascends, the capsules expand and the static pressure drops, causing the altimeter to indicate a higher altitude. The opposite effect occurs when descending, with the advancement in aviation and increased altitude ceiling the altimeter dial had to be altered for use both at higher and lower altitudes. This modification was introduced in the early sixties after the recurrence of air caused by the confusion in the pilots mind. At higher altitudes the window will disappear, the airspeed indicator shows the aircrafts speed relative to the surrounding air. It works by measuring the pressure in the aircrafts Pitot tube relative to the ambient static pressure. The Indicated airspeed must be corrected for pressure and temperature in order to obtain the True airspeed. The instrument is color coded to indicate important airspeeds such as the speed, never-exceed airspeed. The VSI senses changing air pressure, and displays that information to the pilot as a rate of climb or descent in feet per minute, the compass shows the aircrafts heading relative to magnetic north. Errors include Variation, or the difference between magnetic and true direction, and Deviation, caused by the wiring in the aircraft. Additionally, the compass is subject to Dip Errors, while reliable in steady level flight it can give confusing indications when turning, climbing, descending, or accelerating due to the inclination of the Earths magnetic field. For this reason, the indicator is also used for aircraft operation. The attitude indicator shows the relation to the horizon
4.
Mach number
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In fluid dynamics, the Mach number is a dimensionless quantity representing the ratio of flow velocity past a boundary to the local speed of sound. M = u c, where, M is the Mach number, u is the flow velocity with respect to the boundaries. By definition, Mach 1 is equal to the speed of sound, Mach 0.65 is 65% of the speed of sound, and Mach 1.35 is 35% faster than the speed of sound. The local speed of sound, and thereby the Mach number, depends on the condition of the surrounding medium, the Mach number is primarily used to determine the approximation with which a flow can be treated as an incompressible flow. The medium can be a gas or a liquid, the boundary can be the boundary of an object immersed in the medium, or of a channel such as a nozzle, diffusers or wind tunnels channeling the medium. As the Mach number is defined as the ratio of two speeds, it is a dimensionless number, if M <0. 2–0.3 and the flow is quasi-steady and isothermal, compressibility effects will be small and simplified incompressible flow equations can be used. The Mach number is named after Austrian physicist and philosopher Ernst Mach, as the Mach number is a dimensionless quantity rather than a unit of measure, with Mach, the number comes after the unit, the second Mach number is Mach 2 instead of 2 Mach. This is somewhat reminiscent of the modern ocean sounding unit mark, which was also unit-first. In the decade preceding faster-than-sound human flight, aeronautical engineers referred to the speed of sound as Machs number, never Mach 1, Mach number is useful because the fluid behaves in a similar manner at a given Mach number, regardless of other variables. As modeled in the International Standard Atmosphere, dry air at sea level, standard temperature of 15 °C. For example, the atmosphere model lapses temperature to −56.5 °C at 11,000 meters altitude. In the following table, the regimes or ranges of Mach values are referred to, generally, NASA defines high hypersonic as any Mach number from 10 to 25, and re-entry speeds as anything greater than Mach 25. Aircraft operating in this include the Space Shuttle and various space planes in development. Flight can be classified in six categories, For comparison. At transonic speeds, the field around the object includes both sub- and supersonic parts. The transonic period begins when first zones of M >1 flow appear around the object, in case of an airfoil, this typically happens above the wing. Supersonic flow can decelerate back to only in a normal shock. As the speed increases, the zone of M >1 flow increases towards both leading and trailing edges
5.
Altitude
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Altitude or height is defined based on the context in which it is used. As a general definition, altitude is a measurement, usually in the vertical or up direction. The reference datum also often varies according to the context, although the term altitude is commonly used to mean the height above sea level of a location, in geography the term elevation is often preferred for this usage. Vertical distance measurements in the direction are commonly referred to as depth. In aviation, the altitude can have several meanings, and is always qualified by explicitly adding a modifier. Parties exchanging altitude information must be clear which definition is being used, aviation altitude is measured using either mean sea level or local ground level as the reference datum. When flying at a level, the altimeter is always set to standard pressure. On the flight deck, the instrument for measuring altitude is the pressure altimeter. There are several types of altitude, Indicated altitude is the reading on the altimeter when it is set to the local barometric pressure at mean sea level. In UK aviation radiotelephony usage, the distance of a level, a point or an object considered as a point, measured from mean sea level. Absolute altitude is the height of the aircraft above the terrain over which it is flying and it can be measured using a radar altimeter. Also referred to as radar height or feet/metres above ground level, true altitude is the actual elevation above mean sea level. It is indicated altitude corrected for temperature and pressure. Height is the elevation above a reference point, commonly the terrain elevation. Pressure altitude is used to indicate flight level which is the standard for reporting in the U. S. in Class A airspace. Pressure altitude and indicated altitude are the same when the setting is 29.92 Hg or 1013.25 millibars. Density altitude is the altitude corrected for non-ISA International Standard Atmosphere atmospheric conditions, aircraft performance depends on density altitude, which is affected by barometric pressure, humidity and temperature. On a very hot day, density altitude at an airport may be so high as to preclude takeoff and these types of altitude can be explained more simply as various ways of measuring the altitude, Indicated altitude – the altitude shown on the altimeter
6.
Variometer
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It can be calibrated in feet per minute, knots or metres per second, depending on country and type of aircraft. In powered flight the pilot makes frequent use of the VSI to ascertain that level flight is being maintained, in gliding, the instrument is used almost continuously during normal flight, often with an audible output, to inform the pilot of rising or sinking air. It is usual for gliders to be equipped with more than one type of variometer, the simpler type does not need an external source of power and can therefore be relied upon to function regardless of whether a battery or power source has been fitted. The electronic type with audio needs a source to be operative during the flight. The instrument is of little interest during launching and landing, with the exception of aerotow, variometers measure the rate of change of altitude by detecting the change in air pressure as altitude changes. A simple variometer can be constructed by adding a large reservoir to augment the capacity of a common aircraft rate-of-climb instrument. In its simplest electronic form, the instrument consists of an air bottle connected to the atmosphere through a sensitive air flow meter. The faster the aircraft is ascending, the faster the air flows, air flowing out of the bottle indicates that the altitude of the aircraft is increasing. Air flowing into the bottle indicates that the aircraft is descending and these designs tend to be smaller as they do not need the air bottle. They are more reliable as there is no bottle to be affected by changes in temperature, the term vertical speed indicator or VSI is most often used for the instrument when it is installed in a powered aircraft. The term variometer is most often used when the instrument is installed in a glider or sailplane, an Inertial-lead or Instantaneous VSI uses accelerometers to provide a quicker response to changes in vertical speed. Human beings, unlike birds and other flying animals, are not able directly to sense climb, before the invention of the variometer, sailplane pilots found it very hard to soar. Although they could readily detect abrupt changes in speed, their senses did not allow them to distinguish lift from sink. The actual climb/sink rate could not even be guessed at, unless there was some clear fixed visual reference nearby, being near a fixed reference means being near to a hillside, or to the ground. Except when hill-soaring, these are generally very unprofitable positions for glider pilots to be in, the most useful forms of lift are found at higher altitudes and it is very hard for a pilot to detect or exploit them without the use of a variometer. After the variometer was invented in 1929 by Alexander Lippisch and Robert Kronfeld, variometers also became important in foot-launch hang gliding, where the open-to-air pilot hears the wind but needs the variometer to help him or her to detect regions of rising or sinking air. In early hang gliding, variometers were not needed for the short flights or flights close to ridge lift, but the variometer became key as pilots began making longer flights. The first portable variometer for use in hang gliders was the Colver Variometer by Colver Soaring Instruments which served to extend the sport into cross-country thermal flying, as the sport of gliding developed, however, it was found that these very simple uncompensated instruments had their limitations
7.
Aircraft
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An aircraft is a machine that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the lift of an airfoil. The human activity that surrounds aircraft is called aviation, crewed aircraft are flown by an onboard pilot, but unmanned aerial vehicles may be remotely controlled or self-controlled by onboard computers. Aircraft may be classified by different criteria, such as type, aircraft propulsion, usage. Each of the two World Wars led to technical advances. Consequently, the history of aircraft can be divided into five eras, Pioneers of flight, first World War,1914 to 1918. Aviation between the World Wars,1918 to 1939, Second World War,1939 to 1945. Postwar era, also called the jet age,1945 to the present day, 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 gasbags or canopies, filled with a relatively low-density gas such as helium, hydrogen, or hot air, which is less dense than the surrounding air. When the weight of this is added to the weight of the aircraft structure, 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, in the 1930s, large intercontinental flying boats were also sometimes referred to as ships of the air or flying-ships. – though none had yet been built, the advent of powered balloons, called dirigible balloons, and later of rigid hulls allowing a great increase in size, began to change the way these words were used. Huge powered aerostats, characterized by an outer framework and separate aerodynamic skin surrounding the gas bags, were produced. There were still no fixed-wing aircraft or non-rigid balloons large enough to be called airships, then several accidents, such as the Hindenburg disaster in 1937, led to the demise of these airships. Nowadays a balloon is an aerostat and an airship 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. Non-rigid dirigibles are characterized by a moderately aerodynamic gasbag with stabilizing fins at the back and these soon became known as blimps. During the Second World War, this shape was adopted for tethered balloons, in windy weather
8.
Pitot-static system
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A pitot-static system is a system of pressure-sensitive instruments that is most often used in aviation to determine an aircrafts airspeed, Mach number, altitude, and altitude trend. A pitot-static system generally consists of a tube, a static port. Other instruments that might be connected are air data computers, flight recorders, altitude encoders, cabin pressurization controllers. Errors in pitot-static system readings can be dangerous as the information obtained from the pitot static system. Several commercial airline disasters have been traced to a failure of the pitot-static system, the pitot-static system of instruments uses the principle of air pressure gradient. It works by measuring pressures or pressure differences and using these values to assess the speed and these pressures can be measured either from the static port or the pitot tube. The static pressure is used in all measurements, while the pressure is used only to determine airspeed. The pitot pressure is obtained from the pitot tube, the pitot pressure is a measure of ram air pressure, which, under ideal conditions, is equal to stagnation pressure, also called total pressure. The pitot tube is most often located on the wing or front section of an aircraft, facing forward, by situating the pitot tube in such a location, the ram air pressure is more accurately measured since it will be less distorted by the aircrafts structure. When airspeed increases, the ram air pressure is increased, which can be translated by the airspeed indicator, the static pressure is obtained through a static port. The static port is most often a hole on the fuselage of an aircraft. Some aircraft may have a static port, while others may have more than one. In situations where an aircraft has more than one static port, with this positioning, an average pressure can be taken, which allows for more accurate readings in specific flight situations. An alternative static port may be located inside the cabin of the aircraft as a backup for when the static port are blocked. A pitot-static tube effectively integrates the static ports into the pitot probe and it incorporates a second coaxial tube with pressure sampling holes on the sides of the probe, outside the direct airflow, to measure the static pressure. When the aircraft climbs, static pressure will decrease, some pitot-static systems incorporate single probes that contain multiple pressure-transmitting ports that allow for the sensing of air pressure, angle of attack, and angle of sideslip data. Depending on the design, such air data probes may be referred to as 5-hole or 7-hole air data probes, differential pressure sensing techniques can be used to produce angle of attack and angle of sideslip indications. The pitot-static system obtains pressures for interpretation by the pitot-static instruments, while the explanations below explain traditional, mechanical instruments, many modern aircraft use an air data computer to calculate airspeed, rate of climb, altitude and Mach number
9.
Space Shuttle
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The Space Shuttle was a partially reusable low Earth orbital spacecraft system operated by the U. S. National Aeronautics and Space Administration, as part of the Space Shuttle program. Its official program name was Space Transportation System, taken from a 1969 plan for a system of reusable spacecraft of which it was the only item funded for development, the first of four orbital test flights occurred in 1981, leading to operational flights beginning in 1982. Five complete Shuttle systems were built and used on a total of 135 missions from 1981 to 2011, the Shuttle fleets total mission time was 1322 days,19 hours,21 minutes and 23 seconds. Shuttle components included the Orbiter Vehicle, a pair of solid rocket boosters. The Shuttle was launched vertically, like a rocket, with the two SRBs operating in parallel with the OVs three main engines, which were fueled from the ET. The SRBs were jettisoned before the vehicle reached orbit, and the ET was jettisoned just before orbit insertion, at the conclusion of the mission, the orbiter fired its OMS to de-orbit and re-enter the atmosphere. The orbiter then glided as a spaceplane to a landing, usually at the Shuttle Landing Facility of KSC or Rogers Dry Lake in Edwards Air Force Base. After landing at Edwards, the orbiter was back to the KSC on the Shuttle Carrier Aircraft. The first orbiter, Enterprise, was built in 1976 for use in Approach, four fully operational orbiters were initially built, Columbia, Challenger, Discovery, and Atlantis. Of these, two were lost in accidents, Challenger in 1986 and Columbia in 2003, with a total of fourteen astronauts killed. A fifth operational orbiter, Endeavour, was built in 1991 to replace Challenger, the Space Shuttle was retired from service upon the conclusion of Atlantiss final flight on July 21,2011. Nixons post-Apollo NASA budgeting withdrew support of all components except the Shuttle. The vehicle consisted of a spaceplane for orbit and re-entry, fueled by liquid hydrogen and liquid oxygen tanks. The first of four orbital test flights occurred in 1981, leading to operational flights beginning in 1982, all launched from the Kennedy Space Center, Florida. The system was retired from service in 2011 after 135 missions, the program ended after Atlantis landed at the Kennedy Space Center on July 21,2011. Major missions included launching numerous satellites and interplanetary probes, conducting space science experiments, the first orbiter vehicle, named Enterprise, was built for the initial Approach and Landing Tests phase and lacked engines, heat shielding, and other equipment necessary for orbital flight. A total of five operational orbiters were built, and of these and it was used for orbital space missions by NASA, the US Department of Defense, the European Space Agency, Japan, and Germany. The United States funded Shuttle development and operations except for the Spacelab modules used on D1, sL-J was partially funded by Japan
10.
True airspeed
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The true airspeed of an aircraft is the speed of the aircraft relative to the airmass in which it is flying. The true airspeed is important information for accurate navigation of an aircraft, traditionally it is measured using an analogue TAS indicator, but as the Global Positioning System has become available for civilian use, the importance of such analogue instruments has decreased. The IAS meter reads very nearly the TAS at lower altitude, on jet airliners the TAS meter is usually hidden at speeds below 200 knots. Neither provides for accurate speed over the ground, since surface winds or winds aloft are not taken into account and it is the speed normally listed on the flight plan, also used in flight planning, before considering the effects of wind. The airspeed indicator, driven by ram air into a Pitot tube and still air into a static port. The differential pressure is affected by air density, the ratio between the two measurements is temperature-dependent and pressure-dependent, according to the ideal gas law. At sea level in the International Standard Atmosphere and at low speeds where air compressibility is negligible, when the air density or temperature around the aircraft differs from standard sea level conditions, IAS will no longer correspond to TAS, thus it will no longer reflect aircraft performance. The ASI will indicate less than TAS when the air density decreases due to a change in altitude or air temperature, for this reason, TAS cannot be measured directly. In flight, it can be calculated either by using an E6B flight calculator or its equivalent, for low speeds, the data required are static air temperature, pressure altitude and IAS. Above approximately 100 knots, the compressibility error rises significantly and TAS must be calculated by the Mach speed, Mach incorporates the above data including the compressibility factor. Modern aircraft instrumentation use an Air Data Computer to perform this calculation in real time, since temperature variations are of a smaller influence, the ASI error can be roughly estimated as indicating about 2% less than TAS per 1,000 feet of altitude above sea level. For example, an aircraft flying at 15,000 feet in the standard atmosphere with an IAS of 100 knots, is actually flying at 126 knots TAS. At low speeds and altitudes, IAS and CAS are close to equivalent airspeed, for manual calculation of TAS in knots, where Mach number and static air temperature are known, the expression may be simplified to T A S =39 M T. Electronic flight instrument systems contain an air data computer with inputs of impact pressure, static pressure, in order to compute TAS, the air data computer must convert total air temperature to static air temperature. This is also a function of Mach number, T = T t 1 +0.2 M2, in simple aircraft, without an air data computer or Machmeter, true airspeed can be calculated as a function of calibrated airspeed and local air density. Some airspeed indicators incorporate a slide rule mechanism to perform this calculation, otherwise, it can be performed using this applet or a device such as the E6B. Equivalent airspeed Indicated airspeed Calibrated airspeed Flight planning Air Navigation, ISBN 0-273-01120-0 Kermode, A. C. Mechanics of Flight, Chapter 2. ISBN 0-273-31623-0 Gracey, William, Measurement of Aircraft Speed and Altitude, calculate True Airspeed, Mach, Pitot Tube Impact Air Pressure and more at luizmonteiro. com
11.
United States Patent and Trademark Office
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The USPTO is unique among federal agencies because it operates solely on fees collected by its users, and not on taxpayer dollars. The USPTO is based in Alexandria, Virginia, after a 2005 move from the Crystal City area of neighboring Arlington, the head of the USPTO is Michelle K. Lee. She took up her new role on January 13,2014, on March 13, she formally took office as Director after being nominated by President Barack Obama and confirmed by the U. S. Senate. She formerly served as the Director of the USPTOs Silicon Valley satellite office, the USPTO cooperates with the European Patent Office and the Japan Patent Office as one of the Trilateral Patent Offices. The USPTO mission is to maintain a permanent, interdisciplinary historical record of all U. S. patent applications in order to fulfill objectives outlined in the United States Constitution. The legal basis for the United States patent system is Article 1, Section 8, an additional building in Arlington, Virginia, was opened in 2009. The USPTO was expected by 2014 to open its first ever satellite offices in Detroit, Dallas, Denver, the first satellite office opened in Detroit on July 13,2012. In 2013, due to the sequestration, the satellite office for Silicon Valley. However, renovation and infrastructure updates continued after the sequestration, and the Silicon Valley location is due to open in San Jose City Hall in mid-2015. As of September 30,2009, the end of the U. S. governments fiscal year, of those,6,242 were patent examiners and 388 were trademark examining attorneys, the rest are support staff. They are generally newly graduated scientists and engineers, recruited from universities around the nation. They hold degrees in scientific disciplines, but who do not necessarily hold law degrees. Unlike patent examiners, trademark examiners must be licensed attorneys, all examiners work under a strict, count-based production system. For every application, counts are earned by composing, filing, and mailing a first office action on the merits, the Patent Operations of the office is divided into nine different technology centers that deal with various arts. Prior to 2012, decisions of patent examiners may be appealed to the Board of Patent Appeals and Interferences, the United States Supreme Court may ultimately decide on a patent case. Similarly, decisions of trademark examiners may be appealed to the Trademark Trial and Appeal Board, with subsequent appeals directed to the Federal Circuit, under the America Invents Act, the BPAI was converted to the Patent Trial and Appeal Board or PTAB. In recent years, the USPTO has seen increasing delays between when a patent application is filed and when it issues, to address its workload challenges, the USPTO has undertaken an aggressive program of hiring and recruitment. The USPTO hired 1,193 new patent examiners in Fiscal Year 2006,1,215 new examiners in fiscal 2007, in 2006, USPTO instituted a new training program for patent examiners called the Patent Training Academy
12.
Fixed-wing aircraft
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A fixed-wing aircraft is an aircraft, such as an aeroplane, which is capable of flight using wings that generate lift caused by the vehicles forward airspeed and the shape of the wings. Fixed-wing aircraft are distinct from rotary-wing aircraft, in which the form a rotor mounted on a spinning shaft. Glider fixed-wing aircraft, including free-flying gliders of various kinds and tethered kites, powered fixed-wing aircraft that gain forward thrust from an engine include powered paragliders, powered hang gliders and some ground effect vehicles. The wings of an aircraft are not necessarily rigid, kites, hang-gliders, variable-sweep wing aircraft. Most fixed-wing aircraft are flown by a pilot on board the aircraft, kites were used approximately 2,800 years ago in China, where materials ideal for kite building were readily available. Some authors hold that leaf kites were being flown much earlier in what is now Indonesia, by at least 549 AD paper kites were being flown, as it was recorded in that year a paper kite was used as a message for a rescue mission. Ancient and medieval Chinese sources list other uses of kites for measuring distances, testing the wind, lifting men, signaling, and communication for military operations. Stories of kites were brought to Europe by Marco Polo towards the end of the 13th century, although they were initially regarded as mere curiosities, by the 18th and 19th centuries kites were being used as vehicles for scientific research. This machine may have been suspended for its flight, some of the earliest recorded attempts with gliders were those by the 9th-century poet Abbas Ibn Firnas and the 11th-century monk Eilmer of Malmesbury, both experiments injured their pilots. In 1799, Sir George Cayley set forth the concept of the aeroplane as a fixed-wing flying machine with separate systems for lift, propulsion. Cayley was building and flying models of fixed-wing aircraft as early as 1803, in 1856, Frenchman Jean-Marie Le Bris made the first powered flight, by having his glider LAlbatros artificiel pulled by a horse on a beach. In 1884, the American John J. Montgomery made controlled flights in a glider as a part of a series of gliders built between 1883-1886, other aviators who made similar flights at that time were Otto Lilienthal, Percy Pilcher, and Octave Chanute. In the 1890s, Lawrence Hargrave conducted research on wing structures and his box kite designs were widely adopted. Although he also developed a type of aircraft engine, he did not create. Sir Hiram Maxim built a craft that weighed 3.5 tons, in 1894, his machine was tested with overhead rails to prevent it from rising. The test showed that it had enough lift to take off, the craft was uncontrollable, which Maxim, it is presumed, realized, because he subsequently abandoned work on it. By 1905, the Wright Flyer III was capable of fully controllable, stable flight for substantial periods, the flight was certified by the FAI. This was the first controlled flight, to be officially recognised, the Bleriot VIII design of 1908 was an early aircraft design that had the modern monoplane tractor configuration
13.
Airframe
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The airframe of an aircraft is its mechanical structure. It is typically considered to include fuselage, wings and undercarriage, airframe design is a field of aerospace engineering that combines aerodynamics, materials technology and manufacturing methods to achieve balances of performance, reliability and cost. Modern airframe history began in the United States when a 1903 wood biplane made by Orville, in 1912 the Deperdussin Monocoque pioneered the light, strong and streamlined monocoque fuselage formed of thin plywood layers over a circular frame, achieving 210 km/h. Many early developments were spurred by military needs during World War I and these used hybrid wood and metal structures. In 1916 the German Albatros D. German engineer Hugo Junkers first flew all-metal airframes in 1915 with the all-metal, cantilever-wing, commercial aircraft development during the 1920s and 1930s focused on monoplane designs using Radial engines. Some were produced as single copies or in small quantity such as the Spirit of St. Louis flown across the Atlantic by Charles Lindbergh in 1927, william Stout designed the all-metal Ford Trimotors in 1926. They were among the most successful designs to emerge from the era through the use of all-metal airframes, during World War II, military needs again dominated airframe designs. The first jets were produced during the war but not made in large quantity, postwar commercial airframe design focused on airliners, on turboprop engines, and then on Jet engines, turbojets and later turbofans. The generally higher speeds and tensile stresses of turboprops and jets were major challenges, Airbus and Boeing are the dominant assemblers of large jet airliners while ATR, Bombardier and Embraer lead the regional airliner market, many manufacturers produce airframe components. It has a carbon fiber fuselage, said to replace 1,200 sheets of aluminum and 40,000 rivets. In February 2017, Airbus installed a 3D printing machine for titanium aircraft structural parts using electron beam additive manufacturing from Sciaky, airframe production has become an exacting process. Manufacturers operate under strict quality control and government regulations, departures from established standards become objects of major concern. A landmark in aeronautical design, the worlds first jet airliner, early models suffered from catastrophic airframe metal fatigue, causing a series of widely publicised accidents. The Royal Aircraft Establishment investigation at Farnborough Airport founded the science of aircraft crash reconstruction, after 3000 pressurisation cycles in a specially constructed pressure chamber, airframe failure was found to be due to stress concentration, a consequence of the square shaped windows. The windows had been engineered to be glued and riveted, but had been punch riveted only, unlike drill riveting, the imperfect nature of the hole created by punch riveting may cause the start of fatigue cracks around the rivet. The Lockheed L-188 Electra turboprop, first flown in 1957 became a lesson in controlling oscillation. Its 1959 crash of Braniff Flight 542 showed the difficulties that the airframe industry, the A300 had experienced other structural problems but none of this magnitude. Longeron Former Chord Aircraft fairing Vertical stabilizer
14.
Bracing (aeronautics)
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In aeronautics, bracing comprises additional structural members which stiffen the functional airframe to give it rigidity and strength under load. Bracing may be applied both internally and externally, and may take the form of strut, which act in compression or tension as the need arises, and/or wires, which act only in tension. Another disadvantage of bracing wires is that they require routine checking and adjustment, or rigging, during the early years of aviation, bracing was a universal feature of all forms of aeroplane, including the monoplanes and biplanes which were then equally common. Today, bracing in the form of lift struts is still used for light commercial designs where a high wing. Bracing works by creating a triangulated truss structure which resists bending or twisting, by comparison, an unbraced cantilever structure bends easily unless it carries a lot of heavy reinforcement. Making the structure allows it to be much lighter and stiffer. To reduce weight and air resistance, the structure may be made hollow, for example, a high-wing monoplane may be given a diagonal lifting strut running from the bottom of the fuselage to a position far out towards the wingtip. This increases the depth of the wing root to the height of the fuselage. Typically, the ends of bracing struts are joined to the internal structural components such as a wing spar or a fuselage bulkhead. Bracing may be used to resist all the forces which occur in an airframe, including lift, weight, drag. A strut is a bracing component stiff enough to resist these forces whether they place it under compression or tension, a wire is a bracing component able only to resist tension, going slack under compression, and consequently is nearly always used in conjunction with struts. A square frame made of bars is not rigid but tends to bend at the corners. Bracing it with a diagonal bar would be heavy. A wire would be much lighter but would stop it collapsing only one way, to hold it rigid, two cross-bracing wires are needed. This method of cross-bracing can be clearly on early biplanes. Another way of arranging a rigid structure is to make the cross pieces solid enough to act in compression and this method was once common on monoplanes, where the wing and a central cabane or a pylon form the cross members while wire bracing forms the outer diamond. Most commonly found on biplane and other aircraft, wire bracing was also common on early monoplanes. Unlike struts, bracing wires always act in tension The thickness and profile of a wire affect the drag it causes, wires may be made of multi-stranded cable, a single strand of piano wire, or aerofoil sectioned steel
15.
Aircraft canopy
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An aircraft canopy is the transparent enclosure over the cockpit of some types of aircraft. The function of the canopy is to provide a weatherproof and reasonably quiet environment for the aircrafts occupants, the canopy will be as aerodynamically shaped as possible to minimize aerodynamic drag. Very early aircraft had no canopies at all, the pilots were exposed to the wind and weather, although most flying was done in good weather. Through World War I most aircraft had no canopy, although they often had a windshield to deflect the prop wash. In the 1920s and 1930s, the speed and altitude of airplanes necessitated a fully enclosed cockpit. Early canopies were made of pieces of Flat glass held in position by a frame. The muntins reduced visibility, which was problematic for military aircraft. Also, glass canopies were much heavier than acrylic canopies, which were first introduced shortly before World War II, the acrylic bubble canopy was used on aircraft such as the Supermarine Spitfire and Westland Whirlwind, which gave better all-round visibility and reduced weight. It is still being used today on most fighter aircraft and this ruse was inspired by animals and fishes that have similar markings on the head and tail, so they can confuse other creatures. Pilots remain skeptical of this feature, asserting that if the enemy is close enough to see the marking, on many high-performance military aircraft, the canopy is an integral part of the ejection seat system. The pilot cannot be ejected from the aircraft until the canopy is no longer in the path of the ejection seat, in most ejection seat equipped aircraft, the canopy is blown upwards and rearwards by explosive charges. The relative wind then blows the canopy away from the ejection path, in that situation, the pilot could possibly impact the canopy when ejecting. To overcome that possibility, some aircraft have a cord of plastic explosive zig-zagging across the canopy over the pilots head. In the event of an ejection, the cord is activated first. Then the ejection seat are launched through the shattered canopy, a technician must meet the qualifications of E-6 in rank. Most modern acrylic canopies are vacuum formed, a sheet of acrylic is secured to a female mould, then the entire assembly is heated in an oven until the acrylic is pliable. The air is removed from the mould and the acrylic sheet is drawn into it. The acrylic is then trimmed to the shape and attached to an aluminum or composite frame
16.
Aircraft dope
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Aircraft dope is a plasticised lacquer that is applied to fabric-covered aircraft. It tightens and stiffens fabric stretched over airframes, which renders them airtight, typical doping agents include nitrocellulose, cellulose acetate and cellulose acetate butyrate. Liquid dopes are highly flammable, nitrocellulose, for instance, is known as the explosive propellant guncotton. Dopes often include colouring pigments to facilitate even application, and are available in a range of colors. Dope has been applied to various fabrics, including madapolam. Accidents have occurred when dope is not used correctly, for example mixed with other chemicals, used on the wrong fabrics. In the 1930 R101 disaster, improper doping caused the fabric of the airship to become brittle and easily torn
17.
Empennage
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The empennage, also known as the tail or tail assembly, provides stability for aircraft, in a way similar to the feathers on an arrow. The term derives from the French language word empenner which means to feather an arrow, most aircraft feature an empennage incorporating vertical and horizontal stabilising surfaces which stabilise the flight dynamics of yaw and pitch, as well as housing control surfaces. In spite of effective control surfaces, many aircraft that lacked a stabilising empennage were virtually unflyable. Even so-called tailless aircraft usually have a tail fin, heavier-than-air aircraft without any kind of empennage are rare. Structurally, the empennage consists of the tail assembly, including the tailfin, the tailplane. On an airliner this would be all the flying and control surfaces behind the pressure bulkhead. The front section of the tailplane is called the tailplane or horizontal stabiliser and is used to pitch stability. The rear section is called the elevator, and is hinged to the horizontal stabiliser. The elevator is a movable aerofoil that controls changes in pitch, some aircraft employ an all-moving stabiliser and elevators in one unit, known as a stabilator or full-flying stabiliser. The vertical tail structure has a front section called the vertical stabiliser. The rear section of the fin is the rudder, a movable aerofoil that is used to turn the aircrafts nose to one side or the other. When used in combination with the ailerons, the result is a banking turn, some aircraft are fitted with a tail assembly that is hinged to pivot in two axes forward of the fin and stabiliser, in an arrangement referred to as a movable tail. The entire empennage is rotated vertically to actuate the horizontal stabiliser, in some aircraft trim devices are provided to eliminate the need for the pilot to maintain constant pressure on the elevator or rudder controls. The trim device may be, a tab on the rear of the elevators or rudder which act to change the aerodynamic load on the surface. Usually controlled by a wheel or crank. an adjustable stabiliser into which the stabiliser may be hinged at its spar. Usually controlled by a cockpit crank, a bungee trim system which uses a spring to provide an adjustable preload in the controls. Usually controlled by a cockpit lever, an anti-servo tab used to trim some elevators and stabilators as well as increased control force feel. Usually controlled by a wheel or crank
18.
Aircraft fabric covering
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Aircraft fabric covering is a term used for both the material used and the process of covering aircraft open structures. II, in its wrapped Wickelrumpf plywood strip and fabric covering. The purposes of the covering of an aircraft are, To provide a light airproof skin for lifting. To provide structural strength to weak structures. To cover other non-lifting parts of an aircraft to reduce drag, to protect the structure from the elements. Pioneering aviators such as George Cayley and Otto Lilienthal used cotton-covered flying surfaces for their glider designs. The Wright brothers also used cotton to cover their Wright Flyer, other early aircraft used a variety of fabrics, silk and linen being commonly used. Some early aircraft, such as A. V, roes first machines, even used paper as a covering material. Until the development of cellulose based dope in 1911 a variety of methods of finishing the fabric were used, the most popular was the use of rubberised fabrics such as those manufactured by the Continental company. Other methods included the use of sago starch, national insignia painted on the fabric were often cut from downed aircraft and used as war trophies. The German aircraft designer Hugo Junkers is considered one of the pioneers of metal aircraft, the highly flammable mixture of fabric, dope and hydrogen gas was a factor in the demise of the Hindenburg airship. Many transports, bombers and trainers still used fabric, although the flammable nitrate dope was replaced with butyrate dope instead, the Mosquito is an example of a fabric-covered plywood aircraft. The Vickers Wellington used fabric over a geodesic airframe which offered good combat damage resistance, an interesting case of ingenuity under wartime adversity was the Colditz Cock glider. This new fabric could be glued to the airframe instead of sewn, grade A cotton would typically last six to seven years when the aircraft was stored outside, whereas Ceconite, which does not rot like cotton, can last over 20 years. Early attempts to use these modern fabrics with butyrate dope proved that the dope did not adhere at all, nitrate dope was resurrected as the initial system of choice instead, although it was supplanted by new materials too. One fabric system, developed by Ray Stits in the USA and this uses three weights of Dacron fabric sold as by the brand name Ceconite, plus fabric glue for attaching to the airframe, fabric preparation sealer resin and paint. This system is not dope and instead uses vinyl-based chemicals, Ceconite 101 is a certified 3.5 oz/yd² fabric while Ceconite 102 is a 3.16 oz/yd² fabric. There is also an uncertified light Ceconite of 1.87 oz/yd² intended for ultralight aircraft and this method requires physical attachment of the fabric to the airframe in the form of rib-stitching, rivets or capstrips, which are then usually covered with fabric tapes. In addition to Poly-Fiber, a number of companies produce covering processes for certified
19.
Aircraft fairing
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An aircraft fairing is a structure whose primary function is to produce a smooth outline and reduce drag. These structures are covers for gaps and spaces between parts of an aircraft to form drag and interference drag, and to improve appearance. On aircraft, fairings are commonly found on, Cockpit fairing Also called a cockpit pod, commonly made from fiberglass, it may also incorporate a windshield. Elevator and horizontal stabilizer tips Elevator and stabilizer tips fairings smooth out airflow at the tips, the inlet and the nozzle in combination lead to an isotropic speed reduction around the cooling fins and due to the speed-squared law to a reduction in cooling drag. Fin and rudder tips fairings reduce drag at low angles of attack, fillets smooth the airflow at the junction between two components like fuselage and wing, or fuselage and fin. Fixed landing gear junctions Landing gear fairings reduce drag at these junctions, flap track fairings Most jet airliners have a cruising speed between Mach 0.8 and 0.85. For aircraft operating in the regime, wave drag can be minimized by having a cross-sectional area which changes smoothly along the length of the aircraft. This is known as the area rule, on subsonic aircraft such as jet airliners, this can be achieved by the addition of smooth pods on the trailing edges of the wings. These pods are known as anti-shock bodies, Küchemann Carrots, or flap track fairings, spinner To cover and streamline the propeller hub. Strut-to-wing and strut-to-fuselage junctions Strut end fairings reduce drag at these junctions, Tail cones Tail cones reduce the form drag of the fuselage, by recovering the pressure behind it. For the design speed they add no friction drag, Wing root Wing roots are often faired to reduce interference drag between the wing and the fuselage. On top and below the wing it consists of small rounded edge to reduce the surface, Wing tips Wing tips are often formed as complex shapes to reduce vortex generation and so also drag, especially at low speed. Wheels on fixed gear aircraft Wheel fairings are often called wheel pants, speed fairings or, in the UK and they also have the important function of preventing mud and stones from being thrown upwards against the wings or fuselage, or into the propeller on a pusher craft. Bicycle fairing Motorcycle fairing Payload fairing
20.
Fuselage
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The fuselage is an aircrafts main body section. It holds crew, passengers, and cargo, the fuselage also serves to position control and stabilization surfaces in specific relationships to lifting surfaces, which is required for aircraft stability and maneuverability. This type of structure is still in use in lightweight aircraft using welded steel tube trusses. A box truss fuselage structure can also be out of wood—often covered with plywood. Simple box structures may be rounded by the addition of supported lightweight stringers, allowing the fabric covering to form an aerodynamic shape. Geodesic structural elements were used by Barnes Wallis for British Vickers between the wars and into World War II to form the whole of the fuselage, including its aerodynamic shape. In this type of construction multiple flat strip stringers are wound about the formers in opposite spiral directions and this proved to be light, strong, and rigid and had the advantage of being made almost entirely of wood. A similar construction using aluminum alloy was used in the Vickers Warwick with less materials than would be required for other structural types, the geodesic structure is also redundant and so can survive localized damage without catastrophic failure. A fabric covering over the completed the aerodynamic shell. The logical evolution of this is the creation of fuselages using molded plywood, in this method, the exterior surface of the fuselage is also the primary structure. A typical early form of this was built using molded plywood, a later form of this structure uses fiberglass cloth impregnated with polyester or epoxy resin, instead of plywood, as the skin. An example of a larger molded plywood aircraft is the de Havilland Mosquito fighter/light bomber of World War II, no plywood-skin fuselage is truly monocoque, since stiffening elements are incorporated into the structure to carry concentrated loads that would otherwise buckle the thin skin. The use of molded fiberglass using negative molds is prevalent in the production of many modern sailplanes. The use of molded composites for fuselage structures is being extended to large aircraft such as the Boeing 787 Dreamliner. This is the method of constructing an all-aluminum fuselage. First, a series of frames in the shape of the cross sections are held in position on a rigid fixture. These frames are then joined with lightweight longitudinal elements called stringers and these are in turn covered with a skin of sheet aluminum, attached by riveting or by bonding with special adhesives. The fixture is then disassembled and removed from the fuselage shell, which is then fitted out with wiring, controls
21.
Hardpoint
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A hardpoint is a location on an airframe designed to carry an external or internal load. In aeronautics, the station is used to refer to a point of carriage on the frame of an aircraft. A station is rated to carry a certain amount of payload. It is a number which already has taken the rated g-forces of the frame into account. Multiplied by the load factor which the aircraft will sustain when these items are carried. In civilian aviation a station is used to carry an external engine or a fuel tank. As engines are usually a fixed installation, operators usually refer to them with the designation of the engine, therefore, the term is mostly being used for load points meant for non-fixed installation. In the military, a station can also be called weapons station, most stations on a military aircraft serve to carry pods or weapons. A minor number of stations can serve to carry external fuel tanks. These stations are called wet, a general term referring to usage of fuel like wet thrust. The term wet is also carried over to the adapters, such as a pylon, wing stations require pylons to carry objects. The F-111s outermost pair of hardpoints do not swivel, and can only be used while the wing is fully extended and this restricts the aircraft to subsonic flight only while these pylons are fitted, usually fitted with fuel tanks during ferry flights. The pylons are automatically jettisoned if the wing sweep moves past 26 degrees, stations may be numbered for reference or not at all. The numbering is not necessarily consistent and may originate from elsewhere like station 559 on the B-52, there is not necessarily an order in which numbers are assigned. The order can be for example from left to right or vice versa, or mirrored, the often unique centerline station is no exception. A pylon serves to connect the frame of an aircraft to an item or object that is being carried, hence, the use of a pylon is necessary to clear the carriage item of control surfaces as well as prevent undesired disturbance of the flow of air toward the wing. Pylons are usually designed to be aerodynamic to reduce air resistance, there are many different forms, sizes and designs of pylons distinctly termed accordingly like a wedge adaptor or stub wing pylon. Stealth aircraft like the F-22 or F-35 can use jettisonable pylons to retain stealth, while most pylons are part of a modular system which is compatible with numerous stores, certain weapons and aircraft can require special pylons or adapters to carry a specific load
22.
Leading edge
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The leading edge is the part of the wing that first contacts the air, alternatively it is the foremost edge of an airfoil section. The first is a definition, the second a structural one. Associated terms are leading edge radius and leading edge stagnation point, seen in plan the leading edge may be straight or curved. A straight leading edge may be swept or unswept, the meaning that it is perpendicular to the longitudinal axis of the aircraft. As wing sweep is conventionally measured at the 25% chord line an unswept wing may have a swept or tapered leading edge, some aircraft, like the General Dynamics F-111, have swing-wings where the sweep of both wing and leading edge can be varied. In high-speed aircraft, compression heating of the air ahead of the wings can cause heating of the leading edge. Heating was a contributor to the destruction of the Space Shuttle Columbia during re-entry on February 1,2003. When sailing into the wind, the dynamics that propel a sailboat forward are the same that create lift for an airplane, the term leading edge refers to the part of the sail that first contacts the wind. A fine tapered leading edge that does not disturb the flow is desirable since 90% of the drag on a sailboat owing to sails is a result of vortex shedding from the edges of the sail, sailboats utilize a mast to support the sail
23.
Longeron
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In aircraft and launch vehicle construction, a longeron, or stringer or stiffener, is a thin strip of material to which the skin of an aircraft or propellant tank may be fastened. In aircraft fuselage, stringers are attached to formers and run in the direction of the aircraft. They are primarily responsible for transferring the aerodynamic loads acting on the skin onto the frames, in the wings or horizontal stabilizer, longerons run spanwise and attach between the ribs. The primary function here also is to transfer the bending loads acting on the wings onto the ribs, sometimes the terms longeron and stringer are used interchangeably. Historically, though, there is a difference between the two terms. If the longitudinal members in a fuselage are few in number and run all along the fuselage length, the longeron system also requires that the fuselage frames be closely spaced. If the longitudinal members are numerous and are placed just between two formers/frames, then they are called stringers, in the stringer system the longitudinal members are smaller and the frames are spaced farther apart. Generally, longerons are of larger cross-section when compared to stringers, on large modern aircraft the stringer system is more common because it is more weight-efficient, despite being more complex to construct and analyze. Some aircraft use a combination of both stringers and longerons, longerons often carry larger loads than stringers and also help to transfer skin loads to internal structure. Longerons nearly always attach to frames or ribs, stringers often are not attached to anything but the skin, where they carry a portion of the fuselage bending moment through axial loading. It is not uncommon to have a mixture of longerons and stringers in the major structural component. Stringers are also used in the construction of launch vehicle propellant tanks. For example, the Falcon 9 launch vehicle uses stringers in the Kerosene tanks, but not in the Liquid Oxygen tanks, on both the first and second stages
24.
Nacelle
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The nacelle is a housing, separate from the fuselage, that holds engines, fuel, or equipment on an aircraft. The covering is typically aerodynamically shaped and this styling device was much copied within the British industry thereafter, although Czech motorcycle manufacturer Česká Zbrojovka Strakonice was using it beforehand. Indeed, the Royal Enfield Bullet still retains its version, the casquette, the last Triumphs to sport nacelles were the 1966 models of the 6T Triumph Thunderbird 650, 5TA Triumph Speed Twin 500, and 3TA Triumph Twenty One 350. Name for the generator and gearbox shell - with rotator shaft - on a horizontal axis wind turbine, like many aviation terms, the word comes from French, in this case from a word for a small boat
25.
Rib (aeronautics)
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In an aircraft, ribs are forming elements of the structure of a wing, especially in traditional construction. By analogy with the definition of rib, the ribs attach to the main spar. Usually ribs incorporate the airfoil shape of the wing, and the skin adopts this shape when stretched over the ribs, there are several types of ribs. Form-ribs, plate-type ribs, truss ribs, closed-ribs, forged ribs and milled ribs, form-ribs are made from a sheet of metal bent into shape, such as a U-profile. This profile is placed on the skin, just like a stringer, plate-type ribs consist of sheet-metal, which has upturned edges and weight-saving holes cut into it. Truss ribs are built up out of profiles that are joined together and these joints require great attention during design and manufacture. The ribs may be light or heavy in design make them suitable for a wide range of loads. Closed-ribs are constructed from profiles and sheet metal and are suitable for closing off sections of the wing, here too, particular care must be taken with the joints and this type of rib is also suitable for application in a variety of loading conditions. Forged ribs are manufactured using heavy press-machinery, the result is fairly rough, for more refined parts, high-pressure presses are required, which are very expensive. Forged pieces have to further treatment. Forged ribs are used for sections where very high loads apply - near the undercarriage for example and they are manufactured by milling away excess material from a solid block of metal. The shape of these ribs is always accurately defined, such ribs are used under similar conditions as those for forged ribs. Ribs are made out of wood, metal, plastic, composites, the wings of kites, hang gliders, paragliders, powered kites, powered hang gliders, ultralights, windmills are aircraft that have versions that use ribs to form the wing shape
26.
Spar (aeronautics)
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In a fixed-wing aircraft, the spar is often the main structural member of the wing, running spanwise at right angles to the fuselage. The spar carries flight loads and the weight of the wings while on the ground, other structural and forming members such as ribs may be attached to the spar or spars, with stressed skin construction also sharing the loads where it is used. There may be more than one spar in a wing or none at all, however, where a single spar carries the majority of the forces on it, it is known as the main spar. Spars are also used in other aircraft aerofoil surfaces such as the tailplane and fin and serve a similar function, the wing spar provides the majority of the weight support and dynamic load integrity of cantilever monoplanes, often coupled with the strength of the wing D box itself. Together, these two structural components collectively provide the wing rigidity needed to enable the aircraft to fly safely, some of the forces acting on a wing spar are, Upward bending loads resulting from the wing lift force that supports the fuselage in flight. These forces are often offset by carrying fuel in the wings or employing wing-tip-mounted fuel tanks, downward bending loads while stationary on the ground due to the weight of the structure, fuel carried in the wings, and wing-mounted engines if used. Drag loads dependent on airspeed and inertia, chordwise twisting loads due to aerodynamic effects at high airspeeds often associated with washout, and the use of ailerons resulting in control reversal. Further twisting loads are induced by changes of thrust settings to underwing-mounted engines, the D box construction is beneficial to reduce wing twisting. Early aircraft used spars often carved from solid spruce or ash, wooden spars are still being used in light aircraft such as the Robin DR400 and its relatives. Even in modern times, homebuilt aircraft such as the replica Spitfires use laminated wooden spars. These spars are laminated usually from spruce or douglas fir, a number of enthusiasts build replica Spitfires that will actually fly using a variety of engines relative to the size of the aircraft. Larger aircraft using this method of construction may have the spar caps sealed to provide integral fuel tanks. Fatigue of metal wing spars has been a causal factor in aviation accidents. A design aspect of the Supermarine Spitfire wing that greatly to its success was an innovative spar boom design. Two of these booms were linked together by a web, creating a lightweight. A version of this construction method is also used in the BD-5. Many modern aircraft use carbon fibre and Kevlar in their construction, of note are the developments made by Scaled Composites and the German glider manufacturers Schempp-Hirth and Schleicher. These companies initially employed solid fibreglass spars in their designs but now often use carbon fibre in their high performance gliders such as the ASG29, the increase in strength and reduction in weight compared to the earlier fibreglass-sparred aircraft allows a greater quantity of water ballast to be carried
27.
Stabilizer (aeronautics)
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An aircraft stabilizer is an aerodynamic surface, typically including one or more movable control surfaces, that provides longitudinal and/or directional stability and control. A stabilizer can feature a fixed or adjustable structure on which any movable control surfaces are hinged, depending on the context, stabilizer may sometimes describe only the front part of the overall surface. In the conventional configuration, separate vertical and horizontal stabilizers form an empennage positioned at the tail of the aircraft. Other arrangements of the empennage, such as the V-tail configuration, feature stabilizers which contribute to a combination of longitudinal and directional stabilization, Longitudinal stability and control may be obtained with other wing configurations, including canard, tandem wing and tailless aircraft. Some types of aircraft are stabilized with electronic control, in this case, fixed. Transonic flight makes special demands on horizontal stabilizers, since the crossing of the barrier is associated with a sudden move aft of the center of lift. Another role of a stabilizer is to provide longitudinal static stability. Stability can be defined only when the vehicle is in trim and this maintains a constant aircraft attitude, with unchanging pitch angle relative to the airstream, without active input from the pilot. The elevator serve to control the pitch axis, in case of a movable tail. In the conventional configuration the horizontal stabilizer is a horizontal tail or tailplane located to the rear of the aircraft. This is the most common configuration, on many aircraft, the tailplane assembly consists of a fixed surface fitted with a hinged aft elevator surface. Trim tabs may be used to pilot input forces, conversely in some cases, such as small aircraft with all-moving stabilizers. Most airliners and transport aircraft feature a large, slow-moving trimmable tail plane which is combined with independently-moving elevators. The elevators are controlled by the pilot or autopilot and primarily serve to change the attitude, while the whole assembly is used to trim. Many supersonic aircraft feature an all-moving tail assembly, also named stabilator, variants on the conventional configuration include the T-tail, Cruciform tail, Twin tail and Twin-boom mounted tail. Three-surface aircraft such as the Piaggio P, lacking elevators, the tailplanes of these aircraft were not what is now called conventional stabilizers. For example, the Voisin was a layout with a foreplane that was neither stabilizing nor mainly lifting, it was called an équilibreur. In the canard configuration, a wing, or foreplane, is located in front of the main wing
28.
Stressed skin
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In mechanical engineering, stressed skin is a type of rigid construction, intermediate between monocoque and a rigid frame with a non-loaded covering. A stressed skin structure has its compression-taking elements localized and its tension-taking elements distributed, typically, the main frame has rectangular structure and is triangulated by the covering. Sometimes flexible members like wires are used to tension, or rigid compression frames are used, as with a Warren or Pratt truss. When the skin or outer covering is in tension so that it provides a significant portion of the rigidity and this method of construction is lighter than a full frame structure and not as complex to design as a full monocoque. Examples include nearly all modern all-metal airplanes, as well as railway vehicles, buses and motorhomes. The London Transport AEC Routemaster incorporated internal panels riveted to the frames which took most of the shear load. Automobile unibodies are a form a skin as well, as are some framed buildings which lack diagonal bracing. Dornier-Zeppelin D. I, first all-metal stressed skin fighter and first with stressed skin wings Short Silver Streak, stressed Skin Wood to Metal, The Structural Origins of the Modern Airplane
29.
Strut
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A strut is a structural component designed to resist longitudinal compression. Struts provide outwards-facing support in their direction, which can be used to keep two other components separate, performing the opposite function of a tie. They are commonly used in architecture and engineering, as components of an automobile chassis, struts can be passive braces to reinforce the chassis and/or body, or active components of the suspension. This means that a strut must have a more rugged design, the most common form of strut in an automobile is the MacPherson strut. MacPherson struts are often purchased by the automakers in sets of four completed sub-assemblies, the MacPherson strut combines a shock absorber and a spring in a single unit, by means of which each wheel is attached to the car body. 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, in vehicle suspension systems, struts are most commonly an assembly of coil-over spring and shock absorber. Signs of strut failure include a popping or clicking noise when the wheel of the vehicle is turned. This noise is caused by a worn out bearing, most strut failure is gradual, and becomes evident as a more trampoline-like ride, rough travel over bumps, and tire noise/ vibrations. A tendency for the front of the vehicle to nose dive when applying the brakes and to rear upwards when accelerating are other signs of strut failure and these symptoms will only tend to worsen until the struts are replaced with new components. Many strut replacements on non-commercial vehicles are in fact only replacements of the shock absorber, vehicle handling is one of the easiest aspects of a potential new car purchase for a buyer to assess without professional assistance. In piping, struts restrain movement of a component in one direction while allowing movement or contraction in another direction, Strut is a common name in timber framing for a support or brace of scantlings lighter than a post. Frequently struts are found in roof framing from either a tie beam or a king post to a principal rafter, struts may be vertically plumb or leaning and may be straight or curved. In the U. K. Strutting or blocking between floor joists adds strength to the floor system, bracing struts and wires of many kinds were extensively used in early aircraft to stiffen and strengthen, and sometimes even 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 period and remain in use on smaller aircraft today where ultimate performance is not an issue. Typically they are applied to a monoplane and act in tension during flight. Struts have also widely used for purely structural reasons to attach engines, landing gear. The oil-sprung legs of retractable landing gear are still called Oleo struts, 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
30.
T-tail
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A T-tail is an empennage configuration in which the tailplane is mounted to the top of the fin. The arrangement looks like the capital letter T, hence the name, the T-tail differs from the standard configuration in which the tailplane is mounted to the fuselage at the base of the fin. The tailplane is kept out of the disturbed airflow behind the wing and fuselage. Responsive pitch control is crucial for aircraft flying at low speed and this configuration also allows high performance aerodynamics and an excellent glide ratio as the empennage is less affected by wing and fuselage slipstream. The American McDonnell F-101 Voodoo jet fighter suffered from throughout its service life. The vertical stabilizer must be considerably stronger and stiffer to support the forces generated by the tailplane. The T-tail configuration can cause maintenance concerns, the control runs to the elevators are more complex, and elevator surfaces are much more difficult to casually inspect from the ground. The loss of Alaska Airlines Flight 261 was directly attributed to lax maintenance of the T-tail, in order to mitigate some of these drawbacks, a compromise is also possible. The tailplane can be mounted part way up the fin rather than right at the top, the Sud Aviation Caravelle is an example of an aircraft with this configuration
31.
Tailplane
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Not all fixed-wing aircraft have tailplanes. The function of the tailplane is to provide stability and control, in particular, the tailplane helps adjust for changes in the center of pressure or center of gravity caused by changes in speed and attitude, fuel consumption, or dropping cargo or payload. The tailplane comprises the fixed horizontal stabiliser and movable elevator. Besides its planform, it is characterised by, Number of tailplanes - from 0 to 3 Location of tailplane - mounted high, mid or low on the fuselage, fixed stabilizer and movable elevator surfaces, or a single combined stabilator or flying tail. This means that any disturbance which raises the nose produces a pitching moment which tends to raise the nose further. The longitudinal stability of an aircraft may change when it is flown hands-off, i. e. when the controls are subject to aerodynamic forces. In addition to giving a restoring force a tailplane gives damping and this is caused by the relative wind seen by the tail as the aircraft rotates around the center of mass. For example, when the aircraft is oscillating, but is aligned with the overall vehicles motion. Depending on the design and flight regime, its tailplane may create positive lift or negative lift. It is sometimes assumed that on an aircraft this will always be a net down force. On some pioneer designs, such as the Bleriot XI, the center of gravity was between the center of pressure from the wings and the tailplane, which provided positive lift. However this arrangement can be unstable and these often had severe handling issues. Later examples of aircraft from World War I and onwards into the years that had positive lift tailplanes include, chronologically. But with care a lifting tailplane can be made stable, an example is provided by the Bachem Ba 349 Natter VTOL rocket-powered interceptor, which had a lifting tail and was both stable and controllable in flight. In many modern aircraft, the center of gravity is placed ahead of the center of pressure of the main wing. The wing lift then exerts a pitch-down moment around the centre of gravity, a disadvantage is that it generates trim drag. Using a computer to control the elevator allows aerodynamically unstable aircraft to be flown in the same manner, aircraft such as the F-16 are flown with artificial stability. The advantage of this is a significant reduction drag caused by the tailplane, at transonic speeds, an aircraft can experience a shift rearwards in the center of pressure due to the buildup and movement of shockwaves
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Twin tail
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A twin tail is a specific type of vertical stabilizer arrangement found on the empennage of some aircraft. Two vertical stabilizers—often smaller on their own than a conventional tail would be—are mounted at the outside of the aircrafts horizontal stabilizer. Separating the control surfaces allows for additional rudder area or vertical surface without requiring a single tail. On multi-engine propeller designs twin fin and rudders operating in the propeller slipstream give greater rudder authority and improved control at low airspeeds, a twin tail can also simplify hangar requirements, give dorsal gunners enhanced firing area, and in some cases reduce the aircrafts weight. It also affords a degree of one tail is damaged. Many canard aircraft designs incorporate twin tails on the tips of the main wing, very occasionally, three or more tails are used, as on the Breguet Deux-Ponts, Lockheed Constellation and Boeing 314 Clipper. A very unusual design can be seen on the E-2 Hawkeye and this arrangement was chosen for the stringent size limitations of carrier-based aircraft. Significant aircraft with twin tails include the Consolidated B-24 Liberator, Handley-Page Halifax, Avro Lancaster, the arrangement is not limited to World War II-vintage aircraft, however. Airbus has filed a patent for a new, twin-tail, trijet design, cruciform tail Pelikan tail T-tail V-tail
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Vertical stabilizer
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It is analogous to a skeg on boats and ships. On aircraft, vertical stabilizers generally point upwards and these are also known as the vertical tail, and are part of an aircrafts empennage. If the vertical stabilizer was mounted on the underside, it would produce a positive feedback whenever the aircraft dove or banked, the trailing end of the stabilizer is typically movable, and called the rudder, this allows the aircraft pilot to control yaw. Often navigational radio or airband transceiver antennas are placed on or inside the vertical tail, in all known trijets, the vertical stabilizer houses the central engine or engine inlet duct. Vertical stabilizers, or fins, have also used in automobiles, specifically in top level motor sports. A few aircraft models have a fin under the rear end. Normally this is small, or can fold sideways, to allow landing, the vertical stabilizer is mounted exactly vertically, and the horizontal stabilizer is directly mounted to the empennage. This is the most common vertical stabilizer configuration, a T-tail has the horizontal stabilizer mounted at the top of the vertical stabilizer. It is commonly seen on aircraft, such as the Bombardier CRJ200, the Fokker 70, the Boeing 727, the Vickers VC10 and Douglas DC-9. T-tails are often incorporated on configurations with fuselage mounted engines to keep the horizontal stabilizer away from the engine exhaust plume, T-tail aircraft are more susceptible to pitch-up at high angles of attack. This pitch-up results from a reduction in the horizontal stabilizers lifting capability as it passes through the wake of the wing at moderate angles of attack and this can also result in a deep stall condition. T-tails present structural challenges since loads on the stabilizer must be transmitted through the vertical tail. The cruciform tail is arranged like a cross, the most common configuration having the horizontal stabilizer intersecting the vertical tail somewhere near the middle, the PBY Catalina uses this configuration. Falconjets from Dassault always have cruciform tail, rather than a single vertical stabilizer, a twin tail has two. These are vertically arranged, and intersect or are mounted to the ends of the horizontal stabilizer, the Beechcraft Model 18 and many modern military aircraft such as the American F-14, F-15, and F/A-18 use this configuration. A variation on the tail, it has three vertical stabilizers. An example of configuration is the Lockheed Constellation. On the Constellation it was done to give the maximum vertical stabilizer area while keeping the overall height low enough so that it could fit into maintenance hangars
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V-tail
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The aft edge of each twin surface is a hinged control surface which combines the functions of both elevators and rudder. The V-tail, invented and patented in 1930 by Polish engineer Jerzy Rudlicki, has not been a choice for aircraft manufacturers. The X-shaped tail surfaces of the experimental Lockheed XFV were essentially a V tail that extended both above and below the fuselage, the most popular conventionally V-tailed aircraft that was mass-produced is the Beechcraft Bonanza Model 35, often known as the V-tail Bonanza or simply V-Tail. Other examples include the F-117 Nighthawk stealth fighter and the Fouga Magister trainer, the Blohm & Voss P.213 Miniaturjäger was one of the first aircraft having an inverted v-tail. Unmanned aerial vehicles such as the Amber, GNAT and the MQ-1 Predator would later feature this type of tail, the Ultraflight Lazair ultralights, of which over 2000 were produced, also featured an inverted V-tail. Ideally, with fewer surfaces than a conventional three-aerofoil tail or a T-tail, in the mid-1980s, the Federal Aviation Administration grounded the Beechcraft Bonanza due to safety concerns. While the Bonanza met the initial certification requirements, it had a history of fatal mid-air breakups during extreme stress, the type was deemed airworthy and restrictions removed after Beechcraft issued a structural modification as an Airworthiness Directive. Ruddervators are the surfaces on an airplane with a V-tail configuration. They are located at the edge of each of the two airfoils making up the tail of the plane. The first use of ruddervators may have been on the Coandă-1910s X-tail, the later Coandă-1911 flew with ruddervators on its X-tail. Later Polish engineer Jerzy Rudlicki designed the first practical ruddervators in 1930, the name is a portmanteau of the words rudder and elevator. In a conventional aircraft tail configuration, the rudder provides yaw control, ruddervators provide the same control effect as conventional control surfaces, but through a more complex control system that actuates the control surfaces in unison. Yaw moving the nose to the left is produced on an upright V tail by moving the left which deflects the left-hand ruddervator down and left. The opposite produces yaw to the right, pitch nose up is produced by moving the control column or stick back which deflects the left-hand ruddervator up and right and the right-hand ruddervator up and left. Pitch nose down is produced by moving the control column or stick forward which induces the opposite ruddervator movements, cruciform tail Pelikan tail T-tail Twin tail Simple Aerodynamics Of The V-Tail, from Flying the Beech Bonanza by Eckalbar, John C
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Wing root
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The wing root is the part of the wing on a fixed-wing aircraft that is closest to the fuselage. On a simple configuration, this is usually easy to identify. On parasol wing or multiple boom aircraft, the wing may not have a clear root area, wing roots usually bear the highest bending forces in flight and during landing, and they often have fairings to reduce interference drag between the wing and the fuselage. The opposite end of a wing from the root is the wing tip
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Wing tip
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A wing tip is the part of the wing that is most distant from the fuselage of a fixed-wing aircraft. Wing tips are also an expression of aircraft design style, so their shape may be influenced by marketing considerations as well as by aerodynamic requirements. Wing tips are used by aircraft designers to mount navigation lights, anti-collision strobe lights, landing lights, handholds. Wing tip tanks can act as a winglet and distribute more evenly across the wing spar. On fighter aircraft, they may also be fitted with hardpoints, for mounting drop tanks and weapons systems, such as missiles, wingtip mounted hose/drogue systems allow Aerial refueling of multiple aircraft with separation. Aerobatic aircraft use wingtip mounted crosses for visual attitude reference, wingtip mounted smoke systems and fireworks highlight rolling aerobatic maneuvers. Some airshow acts feature the pilot touching or dragging the wingtip along the ground, aircraft with a single main landing gear or very high aspect ratio wings such as gliders, may place small landing gear in the wingtips. Some uncommon designs, like the Rutan Quickie, and Convair XFY placed the landing gear in the wingtips. Some early World War I aircraft used wooded skids on the wingtips to minimize damage on ground looping incidents, several amphibious aircraft such as the Consolidated PBY Catalina, use retractable wingtips as floats. Moveable wingtips can affect the controlability of a wing, wing warping the ends of the wing, produced roll control on the earliest of aircraft such as the Wright Flyer. The North American XB-70 Valkyrie raised and lowered its wingtips in flight to adjust its stability in supersonic and subsonic flight, wingtips can also house the power plant or thrust of an aircraft. The EWR VJ101 used tip mounted jets, the V-22 uses tilting wingtip mounted engines, rotary wing aircraft wingtips may be swept or curved to reduce noise and vibration. Some rotary wing aircraft place their propulsion in wingtip tip jets, the Boeing 777X will feature 3.5 m folding wingtips supplied by Liebherr Aerospace from Lindenberg. The mechanism was demonstrated for Aviation Week at the Boeing Everett Factory in October 2016, the folding takes 20 seconds to complete
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Aircraft flight control system
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Aircraft engine controls are also considered as flight controls as they change speed. The fundamentals of aircraft controls are explained in flight dynamics and this article centers on the operating mechanisms of the flight controls. The basic system in use on aircraft first appeared in a recognizable form as early as April 1908. Throttle controls to control engine speed or thrust for powered aircraft, the control yokes also vary greatly amongst aircraft. Centre sticks also vary between aircraft, some are directly connected to the control surfaces using cables, others have a computer in between which then controls the electrical actuators. Flight control has long been taught in such fashion for decades, as popularized in ab initio instructional books such as the 1944 work Stick. In some aircraft, the surfaces are not manipulated with a linkage. In ultralight aircraft and motorized hang gliders, for example, there is no mechanism at all, instead, the pilot just grabs the lifting surface by hand and moves it. In addition to the flight controls for roll, pitch. Other secondary flight control systems may be available, including slats, spoilers, air brakes, mechanical or manually operated flight control systems are the most basic method of controlling an aircraft. They were used in aircraft and are currently used in small aircraft where the aerodynamic forces are not excessive. Turnbuckles are often used to adjust control cable tension, the Cessna Skyhawk is a typical example of an aircraft that uses this type of system. Gust locks are used on parked aircraft with mechanical systems to protect the control surfaces and linkages from damage from wind. Some aircraft have gust locks fitted as part of the control system and this arrangement can be found on bigger or higher performance propeller aircraft such as the Fokker 50. Some mechanical flight control systems use servo tabs that provide aerodynamic assistance, servo tabs are small surfaces hinged to the control surfaces. The flight control mechanisms move these tabs, aerodynamic forces in turn move and this arrangement was used in early piston-engined transport aircraft and in early jet transports. The Boeing 737 incorporates a system, whereby in the event of total hydraulic system failure. The complexity and weight of mechanical flight control systems increase considerably with the size, hydraulically powered control surfaces help to overcome these limitations
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Aileron
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An aileron is a hinged flight control surface usually 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, movement around this axis is called rolling or banking. The aileron was first patented by the British scientist and inventor Matthew Piers Watt Boulton in 1868, considerable litigation ensued within the United States over the legal issues of lateral roll control, until World War I which compelled the U. S. Government to legislate a legal resolution. The name aileron, from French, meaning wing, also refers to the extremities of a birds wings used to control their flight. It first appeared in print in the 7th edition of Cassells French-English Dictionary of 1877, in the context of powered airplanes it appears in print about 1908. Prior to that, ailerons were often referred to as rudders, their older technical sibling, among the earliest printed aeronautical use of aileron was that in the French aviation journal LAérophile of 1908. He was the first to patent an aileron control system in 1868, Boultons description of his lateral flight control system was both clear and complete. It was the first record we have of appreciation of the necessity for active lateral control as distinguished from, with this invention of Boultons we have the birth of the present-day three torque method of airborne control as was praised by Charles Manly. This was also endorsed by C. H, the fact that the Wright brothers were able to gain a patent in 1906 did not invalidate Boultons lost and forgotten invention. The pioneering U. S. aeronautical engineer Octave Chanute published descriptions and drawings of the Wright brothers 1902 glider in the leading periodical of the day, LAérophile. 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 then published photos of the ailerons on Esnault-Pelterie’s glider which were included in his June 1905 article, 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, ailerons also had the advantage of not weakening the airplanes wing structure as did the wing warping technique, which was one reason for Esnault-Pelteries decision to switch to ailerons. By 1911 most biplanes used ailerons rather than wing warping - by 1915 ailerons had become almost universal on monoplanes as well, the Wright brothers quietly changed their aircraft flight controls from wing warping to the use of ailerons at that time as well. In 1886 his third glider design used rotation of the wing rather than just a trailing edge portion for roll control. By his own all of these changes in addition to his use of an elevator for pitch control provided entire control of the machine in the wind. Both Bullet prototypes crashed during their first flights when their wings broke off in flight due to flutter as a result of being deliberately unbraced. S, the patents importance lay in its claim of a new and useful method of controlling an airplane. Curiously, John J. Montgomery was granted U. S, Patent 831173 at nearly the same time for his methods of wing warping
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Air brake (aeronautics)
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In aeronautics, air brakes or speedbrakes are a type of flight control surfaces used on an aircraft to increase drag or increase the angle of approach during landing. The earliest known air brake was developed in 1931 and deployed on the support struts. Not long after, air brakes located on the bottom of the trailing edge were developed. More modern gliders use airbrakes which may spoil lift as well as increase drag, often, characteristics of both spoilers and air brakes are desirable and are combined - most modern airliner jets feature combined spoiler and air brake controls. In addition, the drag created by the spoilers directly assists the braking effect. Reverse thrust is used to help slow the aircraft after landing. Virtually all jet powered aircraft have an air brake or, in the case of most airliners, many early jets used parachutes as air brakes on approach or after landing. The Blackburn Buccaneer naval strike aircraft designed in the 1950s had a cone that was split. It also helped to reduce the length of the aircraft in the space on an aircraft carrier. The F-15 Eagle, Sukhoi Su-27 and other fighters have an air brake just behind the cockpit, the deceleron is an aileron that functions normally in flight but can split in half such that the top half goes up as the bottom half goes down to brake. This technique was first used on the F-89 Scorpion and has since used by Northrop on several aircraft. The space shuttle used a similar system, the vertically-split rudder opened in clamshell fashion on landing to act as a speed brake, as shown in the accompanying photo. Dive brake Drogue parachute Spoiler Thrust reversal
