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Nap-of-the-earth
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 "contour flying", "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, airborne early warning and control 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 surface-to-air missile and anti-aircraft systems and fighter aircraft. Using NOE flight, the approach may be undetected; the aircraft "pops up" to at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OH-58D Kiowa Treetop
The Bell OH-58 Kiowa is a family of single-engine single-Helicopter rotor, 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 Bell 206, 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 followed, often with uprated engines, enhanced protection systems, and other improvements, culminating in the ''OH-58F''. Additional improvements, such as the ''OH-58X'', were proposed but not pursued. During the 1970s, the US A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar
Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track aircraft, ships, spacecraft, guided missiles, motor vehicles, map weather formations, and terrain. The term ''RADAR'' was coined in 1940 by the United States Navy as an acronym for "radio detection and ranging". The term ''radar'' has since entered English and other languages as an anacronym, a common noun, losing all capitalization. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwave domain, a transmitting antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the objects. Radio waves (pulsed or continuous) from the transmitter reflect off the objects and return to the receiver, giving ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar Horizon
The radar horizon is a critical area of performance for air traffic, aircraft detection systems, defined by the distance at which the radar beam rises enough above the Earth's surface to make detection of a target at the lowest level possible. It is associated with the low elevation region of performance, and its geometry depends on terrain, radar height, and signal processing. This concept 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, th ... [...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 an ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Understory
In forestry and ecology, understory (American English), or understorey (English in the Commonwealth of Nations, Commonwealth English), also known as underbrush or undergrowth, includes plant life growing beneath the Canopy (biology), 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 tolerance, 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 Cornus (genus), dogwood are understory specialists. In Temperate broadleaf and mixed forest, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerial Maneuvers
Aerial may refer to: Music * ''Aerial'' (album), by Kate Bush, and that album's title track * "Aerials" (song), from the album ''Toxicity'' by System of a Down Bands * Aerial (Canadian band) * Aerial (Scottish band) * Aerial (Swedish band) Recreation and sport * Aerial (dance move) * Aerial (skateboarding) * Front aerial, gymnastics move performed in acro dance * Aerial cartwheel * Aerial silk, a form of acrobatics * Aerial skiing Technology * Aerial (radio), a radio ''antenna'' or transducer that transmits or receives electromagnetic waves **Aerial (television), an over-the-air television reception antenna * Aerial photography Other uses * Aerial, Georgia, a community in the United States * ''Aerial'' (magazine), a poetry magazine * ''Aerials'' (film), a 2016 Emirati science-fiction film *''Aerial'', a TV ident for BBC Two from 1997 to 2001 See also * Arial * Ariel (other) * Airiel * Area (other) Area is a quantity of a two-dimensional surfa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wire Strike Protection System
The wire strike protection system (WSPS) is a mechanical wire cutter designed to mitigate the risk of wire strikes while flying helicopters at low level. History Between 1974 and 1979 wire strike accidents accounted for 8% of United States Army Aviation aircraft damage, 6% of aircraft-related injuries, and 16% of aircraft-related fatalities. For the ten years from 1970, 208 civil helicopters were also involved in wire strike accidents; 88 were destroyed (42%) and 37 (11%) of the 331 people involved were killed. The commonest cause of civil helicopter aerial accidents between 1975 and 1977 was striking wires and poles. Bristol Aerospace developed a WSPS qualified for the Bell OH-58 Kiowa under contract to the Canadian Armed Forces in May 1979. Nelson Chan invented WSPS, and was granted patents in 1980. Bristol staged a series of 52 tests of the WSPS by mounting it on the fuselage of a wrecked Kiowa; the fuselage was loaded onto a flatbed truck and driven into wires at speeds rang ... [...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 and infrared detector, infrared detection and to lower the 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 Foot (length), ft), and is often near 2 meters (6 ft). When under attack, a warship can detect sea-skimming missiles only after 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, radar clutter from the sea and similar effects. The ... [...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) / Low-level parachute extraction resupply system (LOLEX) 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. Development 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 A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
