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Terrain Mask
Nap-of-the-earth (NOE) is a type of very low-altitude flight course used by military aircraft to avoid enemy detection and attack in a high-threat environment. Other, mostly older terms include "ground-hugging", "terrain masking", "flying under the radar" and "hedgehopping". During NOE flight, geographical features are used as cover, exploiting valleys and folds in the terrain by flying in, rather than over, them. This keeps the aircraft below enemy air defence radar coverage, avoiding being silhouetted against the sky. Purpose NOE is used to minimize detection by hostile aircraft, AWACS surveillance and control systems, ground-based radar, or attack targets. A high-flying aircraft can be detected by defense systems at long range, giving an air defense system time to react, alerting SAM and AAA systems and fighter aircraft. Using NOE flight, the approach may be undetected; the aircraft "pops up" to attack the target and then turns to escape before the enemy can respond. Dop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OH-58D Kiowa Treetop
The Bell OH-58 Kiowa is a family of single-engine single-rotor military helicopters used for observation, utility, and direct fire support. It was produced by the American manufacturer Bell Helicopter and is closely related to the Model 206A JetRanger civilian helicopter. The OH-58 was originally developed during the early 1960s as the ''D-250'' for the Light Observation Helicopter (LOH). While the rival Hughes OH-6 Cayuse was picked over Bell's submission in May 1965, the company refined its design to create the Model 206A, a variant of which it successfully submitted to the reopened LOH competition two years later. The initial model, designated by the service as the ''OH-58A'', was introduced in May 1969. Successive models would follow, often with uprated engines, enhanced protection systems, and other improvements, cumulating in the ''OH-58F''. Additional improvements, such as the ''OH-58X'', were proposed but ultimately not pursued. During the 1970s, the US Army became in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Understory
In forestry and ecology, understory (American English), or understorey (Commonwealth English), also known as underbrush or undergrowth, includes plant life growing beneath the forest canopy without penetrating it to any great extent, but above the forest floor. Only a small percentage of light penetrates the canopy so understory vegetation is generally shade-tolerant. The understory typically consists of trees stunted through lack of light, other small trees with low light requirements, saplings, shrubs, vines and undergrowth. Small trees such as holly and dogwood are understory specialists. In temperate deciduous forests, many understory plants start into growth earlier in the year than the canopy trees, to make use of the greater availability of light at that particular time of year. A gap in the canopy caused by the death of a tree stimulates the potential emergent trees into competitive growth as they grow upwards to fill the gap. These trees tend to have straight trunks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerial Maneuvers
Aerial may refer to: Music * ''Aerial'' (album), by Kate Bush * ''Aerials'' (song), from the album ''Toxicity'' by System of a Down Bands *Aerial (Canadian band) * Aerial (Scottish band) * Aerial (Swedish band) Performance art * Aerial silk, apparatus used in aerial acrobatics *Aerialist, an acrobat who performs in the air Recreation and sport * Aerial (dance move) *Aerial (skateboarding) *Aerial adventure park, ropes course with a recreational purpose * Aerial cartwheel (or side aerial), gymnastics move performed in acro dance and various martial arts * Aerial skiing, discipline of freestyle skiing *Front aerial, gymnastics move performed in acro dance Technology Antennas *Aerial (radio), a radio ''antenna'' or transducer that transmits or receives electromagnetic waves **Aerial (television), an over-the-air television reception antenna Mechanical *Aerial fire apparatus, for firefighting and rescue *Aerial work platform, for positioning workers Optical *Aer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terrain-following Radar
Terrain-following radar (TFR) is a military aerospace technology that allows a very-low-flying aircraft to automatically maintain a relatively constant altitude above ground level and therefore make detection by enemy radar more difficult. It is sometimes referred to as ''ground hugging'' or ''terrain hugging'' flight. The term ''nap-of-the-earth'' flight may also apply but is more commonly used in relation to low-flying military helicopters, which typically do not use terrain-following radar. TFR systems work by scanning a radar beam vertically in front of the aircraft and comparing the range and angle of the radar reflections to a pre-computed ideal manoeuvring curve. By comparing the distance between the terrain and the ideal curve, the system calculates a manoeuvre that will make the aircraft clear the terrain by a pre-selected distance, often on the order of . Using TFR allows an aircraft to automatically follow terrain at very low levels and high speeds. Terrain-following r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Skimming
Sea skimming is a technique many anti-ship missiles and some fighter or strike aircraft use to avoid radar, infrared detection, and to lower probability of being shot down during their approach to the target. Method Sea-skimming anti-ship missiles try to fly as low as is practically achievable, which is almost always below 50 meters (150 ft), and is often down towards 2 meters (6 ft). When under attack, a warship can detect sea-skimming missiles only once they appear over the horizon (about 28 to 46 km from the ship), allowing about 25 to 60 seconds of warning. Advantages By flying low to the sea, missiles decrease the range at which the target ships can detect them by a significant amount. Flying at a lower altitude increases the amount of time the missile is under the horizon from the perspective of the target ship, making it harder to detect due to radar clutter from the sea and similar effects. The real-life success of sea skimming depends on its e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar Horizon
The radar horizon is a critical area of performance for aircraft detection systems that is defined by the distance at which the radar beam rises enough above the Earth's surface to make detection of a target at low level impossible. It is associated with the low elevation region of performance, and its geometry depends on terrain, radar height, and signal processing. This is associated with the notions of ''radar shadow'', the ''clutter zone'', and the ''clear zone''. Airborne objects can exploit the radar shadow zone and clutter zone to avoid radar detection by using a technique called nap-of-the-earth navigation. Definition Without taking into account the refraction through the atmosphere, the radar horizon would be the geometrical distance D_h from the radar to the horizon only taking into account the height H of the radar above sea-level, and the radius of the earth R_e (approximately 6.4·103 km): :D_h = \sqrt When H is small compared to R_e, this can be approxima ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar Altimeter
A radar altimeter (RA), also called a radio altimeter (RALT), electronic altimeter, reflection altimeter, or low-range radio altimeter (LRRA), measures altitude above the terrain presently beneath an aircraft or spacecraft by timing how long it takes a beam of radio waves to travel to ground, reflect, and return to the craft. This type of altimeter provides the distance between the antenna and the ground directly below it, in contrast to a barometric altimeter which provides the distance above a defined vertical datum, usually mean sea level. Principle As the name implies, radar (radio detection and ranging) is the underpinning principle of the system. The system transmits radio waves down to the ground and measures the time it takes them to be reflected back up to the aircraft. The altitude above the ground is calculated from the radio waves' travel time and the speed of light. Radar altimeters required a simple system for measuring the time-of-flight that could be displayed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low-altitude Parachute-extraction System
The low-altitude parachute-extraction system (LAPES) is a tactical military airlift delivery method where a fixed-wing cargo aircraft can deposit supplies in situations in which landing is not an option, in an area that is too small to accurately parachute supplies from a high altitude. This practice is no longer used in the USAF. This method was developed by the US Military with the assistance of the 109th Quartermaster Company (Air Drop) in 1964. In May 1965, a detachment of the 109th was formed as the 383rd Quartermaster (Aerial Supply) Detachment and sent to Vietnam. In 1966 the 109th was sent to Vietnam and took operational control of the 383rd. Both units provided air drop and LAPES support during the Battle of Khe Sanh in the Vietnam War. LAPES was used to provide a method of supplying heavy loads into Khe Sanh which could not effectively be supplied by air drop. This practice was perfected at Mactan Air Base in Cebu, Philippines. Preparation for a LAPES delivery includ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low Flying Military Training
Low flying military training involves military aircraft flying at low altitude to prepare their aircrew, and other military personnel (e.g. air defence troops), for nap-of-the-earth flying in wartime. The aircraft types can include advanced trainers, ground-attack aircraft, transports and helicopters. Some countries have sufficiently large military reservations for such training to take place without affecting the civilian population. In smaller countries, such as in Europe, there can be tension between the military and the local population—mainly because of aircraft noise. Hazards Low-level flying involves air safety hazards such as: * Collision with the ground, electricity wires etc. as a result of pilot error (e.g. Cavalese, 1998) or failure of aircraft systems - at low level and high speed there is little time to react to any problem. * Mid-air collision with light aircraft (e.g. Norfolk, 1974) or other military aircraft. * Bird strike. The noise can also disturb anim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The New York Times
''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid digital subscribers. It also is a producer of popular podcasts such as '' The Daily''. Founded in 1851 by Henry Jarvis Raymond and George Jones, it was initially published by Raymond, Jones & Company. The ''Times'' has won 132 Pulitzer Prizes, the most of any newspaper, and has long been regarded as a national " newspaper of record". For print it is ranked 18th in the world by circulation and 3rd in the U.S. The paper is owned by the New York Times Company, which is publicly traded. It has been governed by the Sulzberger family since 1896, through a dual-class share structure after its shares became publicly traded. A. G. Sulzberger, the paper's publisher and the company's chairman, is the fifth generation of the family to head the pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cavalese Cable Car Disaster (1998)
The Cavalese cable car crash, also known as the Cermis massacre ( it, Strage del Cermis), occurred on February 3, 1998, near the Italian town of Cavalese, a ski resort in the Dolomites some northeast of Trento. Twenty people were killed when a United States Marine Corps EA-6B Prowler aircraft, flying too low and against regulations, in order for the pilots to "have fun" and "take videos of the scenery", cut a cable supporting a cable car of an aerial lift. The pilot, Captain Richard J. Ashby, and his navigator, Captain Joseph Schweitzer, were put on trial in the United States and found not guilty of involuntary manslaughter and negligent homicide. Later they were found guilty of obstruction of justice and conduct unbecoming an officer and a gentleman for having destroyed a videotape recorded from the plane, and were dismissed from the Marine Corps. The disaster, and the subsequent acquittal of the pilots, strained relations between the U.S. and Italy. Details of the di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally. These attributes allow helicopters to be used in congested or isolated areas where fixed-wing aircraft and many forms of STOL (Short TakeOff and Landing) or STOVL (Short TakeOff and Vertical Landing) aircraft cannot perform without a runway. In 1942, the Sikorsky R-4 became the first helicopter to reach full-scale production.Munson 1968.Hirschberg, Michael J. and David K. Dailey"Sikorsky". ''US and Russian Helicopter Development in the 20th Century'', American Helicopter Society, International. 7 July 2000. Although most earlier designs used more than one main rotor, the configuration of a single main rotor accompanied by a vertical anti-torque tail rotor (i.e. unicopter, not to be confused with the single-blade monocopter) has become the most comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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