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NOTAR Helicopters
NOTAR ("no tail rotor") is a helicopter system which avoids the use of a tail rotor. It was developed by McDonnell Douglas Helicopter Systems (through their acquisition of Hughes Helicopters). The system uses a fan inside the tail boom to build a high volume of low-pressure air, which exits through two slots and creates a boundary layer flow of air along the tailboom utilizing the Coandă effect. The boundary layer changes the direction of airflow around the tailboom, creating thrust opposite the motion imparted to the fuselage by the torque effect of the main rotor. Directional yaw control is gained through a vented, rotating drum at the end of the tailboom, called the direct jet thruster. Advocates of NOTAR believe the system offers quieter and safer operation over a traditional tail rotor. Development The use of directed air to provide anti-torque control had been tested as early as 1945 in the British Cierva W.9. During 1957, a Spanish prototype designed and built by Aer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fort Rucker, Alabama
Fort Rucker is a U.S. Army post located primarily in Dale County, Alabama, United States. It was named for a Civil War officer, Confederate General Edmund Rucker. The post is the primary flight training installation for U.S. Army Aviators and is home to the United States Army Aviation Center of Excellence (USAACE) and the United States Army Aviation Museum. Small sections of the post also lie in Coffee, Geneva, and Houston counties. Part of the Dale County section of the base is a census-designated place; its population was 4,636 at the 2010 census. The main post has entrances from three bordering cities, Daleville, Ozark and Enterprise. In the years before the September 11, 2001 attacks, the main post (except airfields and other restricted areas) was an open post with unmanned gates allowing civilians to drive through. Following the attacks, this policy was changed, and the post is now closed to unauthorized traffic and visitors. It is one of the U.S. Army installations ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synchropter
Intermeshing rotors on a helicopter are a set of two rotors turning in opposite directions, with each rotor mast mounted with a slight angle to the other, in a transversely symmetrical manner, so that the blades intermesh without colliding. The arrangement allows the helicopter to function without a tail rotor, which saves power. However, neither rotor lifts directly vertically, which reduces efficiency per each rotor. This configuration is sometimes referred to as a synchropter. Yaw is accomplished through varying torque, which is done by increasing collective pitch on one of the blade sets. Most intermeshing designs have two blades per mast, although exceptions such as the Kellett XR-10 with three blades per mast do exist. The arrangement was developed in Germany by Anton Flettner for a small anti-submarine warfare helicopter, the Flettner Fl 265 as the pioneering example, and later the Flettner Fl 282 Kolibri. During the Cold War the American Kaman Aircraft company p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tandem Rotors
Tandem, or in tandem, is an arrangement in which a team of machines, animals or people are lined up one behind another, all facing in the same direction. The original use of the term in English was in ''tandem harness'', which is used for two or more draft horses, or other draft animals, harnessed in a single line one behind another, as opposed to a pair, harnessed side by side, or a team of several pairs. The tandem harness allows additional animals to provide pulling power for a vehicle designed for a single animal. The English word ''tandem'' derives from the Latin adverb , meaning ''at length'' or ''finally''. It is a word play, using the Latin phrase (referring to time, not position) for English "at length, lengthwise". Tandem bicycles are named for their tandem seating, a more common arrangement than side-by-side "sociable" seating. ''Tandem'' can also be used more generally to refer to any group of persons or objects working together, not necessarily in line. Automob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coaxial Rotors
Coaxial rotors or coax rotors are a pair of helicopter rotors mounted one above the other on concentric shafts, with the same axis of rotation, but turning in opposite directions (contra-rotating). This rotor configuration is a feature of helicopters produced by the Russian Kamov helicopter design bureau. History The idea of coaxial rotors originates with Mikhail Lomonosov. He had developed a small helicopter model with coaxial rotors in July 1754 and demonstrated it to the Russian Academy of Sciences. In 1859, the British Patent Office awarded the first helicopter patent to Henry Bright for his coaxial design. From this point, coaxial helicopters developed into fully operational machines as we know them today. Two pioneering helicopters, the Corradino D'Ascanio-built "D'AT3" of 1930, and the generally more successful French mid-1930s ''Gyroplane Laboratoire'', both used coaxial rotor systems for flight. Design considerations Having two coaxial sets of rotors provides sym ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tip Jet
A tip jet is a jet nozzle at the tip of some helicopter rotor blades, used to spin the rotor, much like a Catherine wheel firework. Tip jets replace the normal shaft drive and have the advantage of placing no torque on the airframe, thus not requiring the presence of a tail rotor. Some simple monocopters are composed of nothing but a single blade with a tip rocket. Tip jets can use compressed air, provided by a separate engine, to create jet thrust. Other types use a system that functions similarly to the afterburner (reheat) on a conventional jet engine, except that instead of reheating a gas jet, they serve as the primary heater, creating greater thrust than the flow of pre-compressed air alone; the best description of this is ''thrust augmentation''. Other designs includes ramjets or even a complete turbojet engine. Some, known as Rocket On Rotor systems, involve placing rockets on the tips of the rotor blades that are fueled from an onboard fuel tank. If the helicopter's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fenestron
A Fenestron (sometimes alternatively referred to as a fantail or a "fan-in-fin" arrangementLeishman 2006, p. 321.) is an enclosed helicopter tail rotor that operates like a ducted fan. The term ''Fenestron'' is a trademark of multinational helicopter manufacturing consortium Airbus Helicopters (formerly known as Eurocopter). The word itself comes from the Occitan term for a ''small window'', and is ultimately derived from the Latin word ''fenestra'' for ''window''.Prouty, Ray. ''Helicopter Aerodynamics'', Helobooks, 1985, 2004. p. 266. The Fenestron differs from a conventional open tail rotor by being integrally housed within the tail boom, and like the conventional tail rotor it replaces, functions to counteract the torque generated by the main rotor. While conventional tail rotors typically have two or four blades, Fenestrons have between seven and eighteen blades; these may have variable angular spacing so that the noise is distributed over different frequencies. By placing t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Youngcopter Neo
The Youngcopter Neo () is a German NOTAR helicopter that was designed by Björn Jung and is under development by his company, Youngcopter of Mainz. It was first publicly introduced at the ILA Berlin Air Show in 2008. The aircraft is intended to be supplied as a kit for amateur construction.Tacke, Willi; Marino Boric; et al: ''World Directory of Light Aviation 2015-16'', page 212. Flying Pages Europe SARL, 2015. No projected date has been announced for kit deliveries and no pricing has been set as of January 2018. Design and development The Neo was designed to comply with the amateur-built aircraft construction rules. The first prototype was completed in 2008 and ground run. By 2010 ground testing had been completed, including rotor system tracking and balancing. The prototype first flew in hovering flight on 31 October 2011 and developmental hover flight testing continued through 2015. The Neo design features a single main rotor, with no tail rotor, a two-seats-in side-by-s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MD Helicopters MD 600
The MD Helicopters MD 600N is a light utility civilian helicopter designed in the United States. It is a stretched eight-seat development of the five-seat MD 520N helicopter. Design and development McDonnell Douglas Helicopter Systems (MD Helicopters since 1999) first announced it was developing a stretched MD 520N in late 1994, at that time designated the MD 630N.Frawley, Gerard: ''The International Directory of Civil Aircraft, 2003–2004'', page 156. Aerospace Publications Pty Ltd, 2003. . The prototype, a modified MD 530F, had made its first flight on November 22, 1994. McDonnell Douglas gave the go-ahead for the production aircraft, redesignated the MD 600N, in March 1995. McDonnell Douglas stretched the MD 520N fuselage by inserting a plug aft of the cockpit/cabin bulkhead and stretching the NOTAR tail boom. The larger fuselage allows for an extra (middle) row of seats. Other differences compared with the MD 520N include a new six blade main rotor (the MD 520N has a five ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MD Helicopters MD 500
The MD Helicopters MD 500 series is an American family of light utility civilian and military helicopters. The MD 500 was developed from the Hughes 500, a civilian version of the US Army's OH-6A Cayuse/Loach. The series currently includes the MD 500E, MD 520N, and MD 530F. The MD 500 was initially produced by Hughes Helicopters as the ''Hughes 500''. Since being introduced in 1967, numerous models have been produced, often featuring a more powerful engine or a five-bladed main rotor in place of the original four-blade counterpart. The MD 500 has been commonly used for utility work, particularly the ''MD 530F''; it has also proven to be popular with law enforcement agencies. Production of the type was continued into the twenty-first century by Hughes' successor companies, McDonnell Douglas Helicopter Systems, and subsequently MD Helicopters. While the MD 500 series has been largely operated by civil customers, it has occasionally seen military use, even to the extent of performi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Belgium Police 520N (cropped)
Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to the southwest, and the North Sea to the northwest. It covers an area of and has a population of more than 11.5 million, making it the 22nd most densely populated country in the world and the 6th most densely populated country in Europe, with a density of . Belgium is part of an area known as the Low Countries, historically a somewhat larger region than the Benelux group of states, as it also included parts of northern France. The capital and largest city is Brussels; other major cities are Antwerp, Ghent, Charleroi, Liège, Bruges, Namur, and Leuven. Belgium is a sovereign state and a federal constitutional monarchy with a parliamentary system. Its institutional organization is complex and is structured on both regional and linguistic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MD Helicopters MD Explorer
The MD Helicopters MD Explorer is a light twin-engined utility helicopter designed and initially produced by the American rotorcraft specialist McDonnell Douglas Helicopter Systems. On 18 December 1992, the maiden flight was conducted, initial certification for the type followed roughly two years later. The initial model, the MD 900, was joined by an improved successor, the MD 902, during the late 1990s. The Explorer is currently produced by MD Helicopters. Development In January 1989, McDonnell Douglas Helicopters officially announced the launch of the Explorer, which it initially referred to as the ''MDX''. Amongst other things, the Explorer was the first McDonnell Douglas helicopter to incorporate the NOTAR system from its initial design.Frawley 2003, p. 156. McDonnell Douglas partnered with Hawker de Havilland of Australia, which handled the manufacturing of the airframes. A total of ten prototypes were constructed, seven of which being used for ground-based tests. McDonnel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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