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Phugoid
In aviation, a phugoid or fugoid () is an aircraft motion in which the vehicle Aircraft principal axes, pitches up and climbs, and then pitches down and descends, accompanied by speeding up and slowing down as it goes "downhill" and "uphill". This is one of the basic aircraft dynamic modes, flight dynamics modes of an fixed-wing aircraft, aircraft (others include short period, Aircraft_dynamic_modes#Roll_subsidence_mode, roll subsidence, dutch roll, and spiral divergence). Detailed description The phugoid has a nearly constant angle of attack but varying pitch (flight), pitch, caused by a repeated exchange of airspeed and altitude. It can be excited by an elevator (aircraft), elevator singlet (a short, sharp deflection followed by a return to the centered position) resulting in a pitch (flight), pitch increase with no change in trim tab, trim from the cruise (flight), cruise condition. As speed decays, the nose drops below the horizon. Speed increases, and the nose climbs above t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spiral Divergence
The dynamic stability of an aircraft refers to how the aircraft behaves after it has been disturbed following steady non-oscillating flight. Longitudinal modes Oscillating motions can be described by two parameters, the period of time required for one complete oscillation, and the time required to damp to half-amplitude or the time to double the amplitude for a dynamically unstable motion. The longitudinal motion consists of two distinct oscillations, a long-period oscillation called a phugoid mode and a short-period oscillation referred to as the short-period mode. Phugoid (longer period) oscillations The longer period mode, called the "phugoid mode," is the one in which there is a large-amplitude variation of air-speed, pitch angle, and altitude, but almost no angle-of-attack variation. The phugoid oscillation is a slow interchange of kinetic energy (velocity) and potential energy (height) about some equilibrium energy level as the aircraft attempts to re-establish the equi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Short Period
The dynamic stability of an aircraft refers to how the aircraft behaves after it has been disturbed following steady non-oscillating flight. Longitudinal modes Oscillating motions can be described by two parameters, the period of time required for one complete oscillation, and the time required to damp to half-amplitude or the time to double the amplitude for a dynamically unstable motion. The longitudinal motion consists of two distinct oscillations, a long-period oscillation called a phugoid mode and a short-period oscillation referred to as the short-period mode. Phugoid (longer period) oscillations The longer period mode, called the "phugoid mode," is the one in which there is a large-amplitude variation of air-speed, pitch angle, and altitude, but almost no angle-of-attack variation. The phugoid oscillation is a slow interchange of kinetic energy (velocity) and potential energy (height) about some equilibrium energy level as the aircraft attempts to re-establish the eq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aircraft Dynamic Modes
The dynamic stability of an aircraft refers to how the aircraft behaves after it has been disturbed following steady non-oscillating flight. Longitudinal modes Oscillating motions can be described by two parameters, the period of time required for one complete oscillation, and the time required to damp to half-amplitude or the time to double the amplitude for a dynamically unstable motion. The longitudinal motion consists of two distinct oscillations, a long-period oscillation called a phugoid mode and a short-period oscillation referred to as the short-period mode. Phugoid (longer period) oscillations The longer period mode, called the "phugoid mode," is the one in which there is a large-amplitude variation of air-speed, pitch angle, and altitude, but almost no angle-of-attack variation. The phugoid oscillation is a slow interchange of kinetic energy (velocity) and potential energy (height) about some equilibrium energy level as the aircraft attempts to re-establish the equi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pilot-induced Oscillation
Pilot-induced oscillations (PIOs), as defined by MIL-HDBK-1797A, are ''sustained or uncontrollable oscillations resulting from efforts of the pilot to control the aircraft''. They occur when the aviator, pilot of an aircraft inadvertently commands an often increasing series of corrections in opposite directions, each an attempt to cover the aircraft's reaction to the previous input with an overcorrection in the opposite direction. An aircraft in such a condition can appear to be "porpoising" switching between upward and downward directions. As such it is a coupling of the frequency of the pilot's inputs and the aircraft's own frequency. In order to avoid any assumption that oscillation is necessarily the fault of the pilot, new terms have been suggested to replace ''pilot-induced oscillation''. These include ''aircraft-pilot coupling'', ''pilot–in-the-loop oscillations'' and ''pilot-assisted (or augmented) oscillations''. The physics of flight make such oscillations more probab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbine Engine Failure
A turbine engine failure occurs when a gas turbine engine unexpectedly stops producing power due to a malfunction other than fuel exhaustion. It often applies for aircraft, but other turbine engines can also fail, such as ground-based turbines used in power plants or combined diesel and gas vessels and vehicles. Reliability Turbine engines in use on today's turbine-powered aircraft are very reliable. Engines operate efficiently with regularly scheduled inspections and maintenance. These units can have lives ranging in the tens of thousands of hours of operation. However, engine malfunctions or failures occasionally occur that require an engine to be shut down in flight. Since multi-engine airplanes are designed to fly with one engine inoperative and flight crews are trained for that situation, the in-flight shutdown of an engine typically does not constitute a serious safety of flight issue. The Federal Aviation Administration (FAA) was quoted as stating turbine engines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydraulic System
Hydraulics () is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counterpart of pneumatics, which concerns gases. Fluid mechanics provides the theoretical foundation for hydraulics, which focuses on applied engineering using the properties of fluids. In its fluid power applications, hydraulics is used for the generation, control, and transmission of power by the use of pressurized liquids. Hydraulic topics range through some parts of science and most of engineering modules, and they cover concepts such as pipe flow, dam design, fluidics, and fluid control circuitry. The principles of hydraulics are in use naturally in the human body within the vascular system and erectile tissue. ''Free surface hydraulics'' is the branch of hydraulics dealing with free surface flow, such as occurring in rivers, canals, lakes, estuaries, and seas. Its sub-f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United Airlines Flight 232
United Airlines Flight 232 was a regularly scheduled United Airlines flight from Stapleton International Airport in Denver to O'Hare International Airport in Chicago, continuing to Philadelphia International Airport. On July 19, 1989, the DC-10 (registered as N1819U) serving the flight crash-landed at Sioux Gateway Airport in Sioux City, Iowa, after suffering a catastrophic failure of its tail-mounted engine due to an unnoticed manufacturing defect in the engine's fan disk, which resulted in the loss of all flight controls. Of the 296 passengers and crew on board, 112 died during the accident, while 184 people survived. Thirteen of the passengers were uninjured. It was the deadliest single-aircraft accident in the history of United Airlines. Despite the fatalities, the accident is considered a good example of successful crew resource management, a new concept at the time. Contributing to the outcome was the crew's decision to recruit the assistance of a company check pilot, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Knot (unit)
The knot () is a unit of speed equal to one nautical mile per hour, exactly (approximately or ). The ISO standard symbol for the knot is kn. The same symbol is preferred by the Institute of Electrical and Electronics Engineers ( IEEE), while kt is also common, especially in aviation, where it is the form recommended by the International Civil Aviation Organization ( ICAO). The knot is a non- SI unit. The knot is used in meteorology, and in maritime and air navigation. A vessel travelling at 1 knot along a meridian travels approximately one minute of geographic latitude in one hour. Definitions ;1 international knot = :1 nautical mile per hour (by definition), : (exactly), : (approximately), : (approximately), : (approximately) : (approximately). The length of the internationally agreed nautical mile is . The US adopted the international definition in 1954, having previously used the US nautical mile (). The UK adopted the international nautical mile defi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Takamagahara
Mount Takamagahara (高天原山, ''Takamagahara-yama'') is a mountain in the Gunma Prefecture of Japan, near Ueno village. It is tall. Takamagahara is the world of heaven in Japanese mythology. The crash of Japan Air Lines Flight 123 on 12 August 1985 was initially reported on Mount Osutaka, but later confirmed to be on the ridge of Mount Takamagahara at a height of approximately above sea level. With the loss of 520 people, it remains the deadliest single-aircraft accident in aviation history. britannica.com; accessed 16 August 2015. This area was later renamed as ''Osutaka no One'' ("Mountain Ridge of Mount Osutaka") by the village mayor of Ueno, Takeo Kurosawa (Former |
Aft Pressure Bulkhead
The aft pressure bulkhead or rear pressure bulkhead is the rear component of the pressure seal in all aircraft that cruise in a tropopause zone in the Earth's atmosphere. It helps maintain pressure when stratocruising and protects the aircraft from bursting due to the higher internal pressure. Design Aft pressure bulkheads can either be curved, which reduces the amount of metal needed at the cost of reducing the usable space in the airliner, or flat, which gives more internal space but also more weight. Patents have been filed that propose deliberately creating cavities within the rear bulkhead with the purpose of providing more usable cabin space. On several airliners, production of the rear pressure bulkhead has been outsourced to third party manufacturers. While typically being a time-consuming and somewhat uncommon process, an aircraft's aft pressure bulkhead can be wholly replaced. During the twenty-first century, various parties became increasingly interested in developing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Japan Air Lines Flight 123
Japan Air Lines Flight 123 was a scheduled domestic passenger flight from Tokyo to Osaka, Japan. On August12, 1985, the Boeing 747 flying the route suffered a severe structural failure and explosive decompression 12 minutes after takeoff. After flying under minimum control for 32 minutes, the plane crashed in the area of Mount Takamagahara, 100kilometres () from Tokyo. The aircraft, featuring a high-density seating configuration, was carrying 524people. The crash killed all 15crew members and 505 of the 509 passengers on board, leaving only four survivors. An estimated 20 to 50 passengers survived the initial crash but died from their injuries while awaiting rescue. The crash is the list of aircraft accidents and incidents resulting in at least 50 fatalities, deadliest single-aircraft accident in aviation history and remains the deadliest aviation incident in Japan. Japan's Aircraft Accident Investigation Commission (AAIC), assisted by the U.S. National Transportation Safety Boar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
