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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 compa ...
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Kaman K-225
The Kaman K-225 is an American experimental helicopter developed by Kaman Aircraft. One example was modified to become the world's first gas turbine-powered helicopter. Design and development The K-125 was Charles Kaman's first helicopter, which utilized intermeshing rotors and Kaman's patented servo-flap stability control."Hall of Fame/Inventor Profile: Charles Kaman" The K-125 first flew on 15 January 1947. The K-190 and K-225 were an improved versions of the K-125, which first flew in April and July 1949 respectively. The U.S. Navy bought two and the Coast Guard one for $25,000 each. The United States Air Force evaluated one K-225 with the designation YH-22. A modified K-225 equipped with a Boeing 502 (YT50) turboshaft engine became the first gas turbine-powered helicopter in December 1951. This aircraft is now at the Smithsonian Institution in Washington, D.C. A standard K-225 is preserved in the New England Air Museum at Windsor Locks Connecticut. In 1953, the Turkish ...
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Kellett XR-10
The Kellett XR-10 was a military transport helicopter developed in the United States in the 1940s that only flew in prototype form. It was designed in response to a USAAF Technical Instruction issued for the development of a helicopter to transport passengers, cargo, or wounded personnel within an enclosed fuselage. Kellett's proposal followed the general layout that the company was developing in the XR-8, with twin intermeshing rotors 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. T ..., and was accepted by the Air Force on 16 October over proposals by Sikorsky, Bell, and Platt-LePage. The XR-10 resembled a scaled-up XR-8, although its twin engines were carried in nacelles at the fuselage sides, driving the rotors via long driveshafts, and the aircraft was skinned entirely in metal ...
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Kaman K-MAX
The Kaman K-MAX (company designation K-1200) is an American helicopter with intermeshing rotors (synchropter) by Kaman Aircraft. It is optimized for external cargo load operations, and is able to lift a payload of over , which is more than the helicopter's empty weight. An unmanned aerial vehicle version with optional remote control has been developed and evaluated in extended practical service in the war in Afghanistan. After being out of production for more than a decade, in June 2015 Kaman announced it was restarting production of the K-MAX due to it receiving ten commercial orders.Kaman restarts K-Max production on new commercial orders
Flightglobal
The first flight of a K-MAX from the restarted production took place in May ...
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HH-43 Huskie
The Kaman HH-43 Huskie is a helicopter with intermeshing rotors used by the United States Air Force, the United States Navy and the United States Marine Corps from the 1950s until the 1970s. It was primarily used for aircraft firefighting and rescue in the close vicinity of air bases, but was later used as a short-range overland search and rescue aircraft during the Vietnam War. Under the aircraft designation system used by the U.S. Navy pre-1962, Navy and U.S. Marine Corps versions were originally designated as the HTK, HOK or HUK, for their use as training, observation or utility aircraft, respectively. Design and development In 1947 Anton Flettner, a German aviation engineer, was brought to New York in the United States as part of Operation Paperclip. He was the developer of Germany's Flettner Fl 282 "Kolibri" (Hummingbird), a helicopter employing the "synchropter" principle of intermeshing rotors, a unique design principle that dispenses with the need for a tail rotor. Fle ...
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Flettner Fl 282
The Flettner Fl 282 ''Kolibri'' ("Hummingbird") is a single-seat intermeshing rotor helicopter, or ''synchropter'', produced by Anton Flettner of Germany. According to Yves Le Bec, the Flettner Fl 282 was the world's first series production helicopter. Design and development The Fl 282 ''Kolibri'' was an improved version of the Flettner Fl 265 announced in July 1940, which pioneered the same intermeshing rotor configuration that the ''Kolibri'' used. It had a 7.7 litre displacement, seven-cylinder Siemens-Halske Sh 14 radial engine of mounted in the center of the fuselage, with a transmission mounted on the front of the engine from which a drive shaft ran to an upper gearbox, which then split the power to a pair of opposite-rotation drive shafts to turn the rotors. The Sh 14 engine was a venerable, tried-and-true design with low specific power output and low power/weight ratio (20.28 hp/L, 0.54 hp/lb) which could (anecdotally) run for up to 400 hours without major se ...
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Flettner Fl 265
The Flettner Fl 265 was an experimental helicopter designed by Anton Flettner. Design and development This helicopter, developed in 1938 with the support of Nazi Germany's ''Kriegsmarine'', made it possible, for the first time, to transition from powered rotary-wing flight to autorotation and back again, making it the safest helicopter of its time. In contrast to the Fl 185, the Fl 265, believed to be the pioneering example of a synchropter, had two intermeshing rotors 12 m in diameter, powered by a 160 hp (119 kW) BMW-Bramo Sh 14 A radial engine in the nose of the fuselage, fitted with a fan to assist cooling. Six helicopters were constructed, but series production was curtailed in favour of the Flettner Fl 282. Operators ; *''Luftwaffe The ''Luftwaffe'' () was the aerial-warfare branch of the German '' Wehrmacht'' before and during World War II. Germany's military air arms during World War I, the '' Luftstreitkräfte'' of the Imperial Army and the ...
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Kellett XR-8
The Kellett XR-8 (later redesignated XH-8) was a helicopter built in the United States during World War II. It was a two-seat machine intended to demonstrate the feasibility of a twin-rotor system and, while it accomplished this, it also demonstrated a number of problems that prevented further development of this particular design. Design and development The successful demonstration of the Sikorsky VS-300 had the USAAF favoring the helicopter over the autogiro as an approach to rotary-winged flight. Realizing this, the Kellett Autogiro Corporation made a proposal to the USAAF on 11 November 1942 for the development of a twin-rotor helicopter that would eliminate the need for a tail rotor and its attendant loss of power. Initially discounted on theoretical grounds, the proposal was re-examined in the light of tests done with models by the Army's Experimental Engineering Section, and was accepted on 7 January the following year. This was followed on 11 September with a contract ...
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Kaman HH-43 Huskie
The Kaman HH-43 Huskie is a helicopter with intermeshing rotors used by the United States Air Force, the United States Navy and the United States Marine Corps from the 1950s until the 1970s. It was primarily used for aircraft firefighting and rescue in the close vicinity of air bases, but was later used as a short-range overland search and rescue aircraft during the Vietnam War. Under the aircraft designation system used by the U.S. Navy pre-1962, Navy and U.S. Marine Corps versions were originally designated as the HTK, HOK or HUK, for their use as training, observation or utility aircraft, respectively. Design and development In 1947 Anton Flettner, a German aviation engineer, was brought to New York in the United States as part of Operation Paperclip. He was the developer of Germany's Flettner Fl 282 "Kolibri" (Hummingbird), a helicopter employing the "synchropter" principle of intermeshing rotors, a unique design principle that dispenses with the need for a tail rotor. Fl ...
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SNCAC NC
SNCAC (the ', sometimes known as ) was a French aircraft manufacturer created by the nationalisation of the Farman Aviation Works and Hanriot firms in 1936. It was liquidated in 1949, with assets distributed between SNCAN, SNCASO, and SNECMA, all of which were nationalised firms. Aircraft *SNCAC NC.130 * SNCAC NC.150 * SNCAC NC 211 Cormoran *SNCAC NC.270 *SNCAC NC-290 - abandoned project for a four-engined ( Nene-powered) jet transport for 60 passengers. *SNCAC NC.420 *Farman NC.470 * SNCAC NC.510 * SNCAC NC.530 * SNCAC NC-600 *SNCAC NC.701 Martinet *SNCAC NC.702 Martinet *SNCAC NC.800 Cab - abandoned project for a light twin-engined transport * NC.832 Chardonneret * NC.840 Chardonneret * NC.841 Chardonneret * SNCAC NC.851 * SNCAC NC.853 *SNCAC NC.854 * SNCAC NC.855 * SNCAC NC.856 *SNCAC NC.900 *SNCAC NC.1070 *SNCAC NC.1071 * SNCAC NC 1080 *SNCAC NC.2001 Abeille *SNCAC NC.3021 Belphégor The SNCAC NC.3021 Belphégor was a French high altitude research aircraft designed an ...
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Praga E-1
Praga is a district of Warsaw, Poland. It is on the east bank of the river Vistula. First mentioned in 1432, until 1791 it formed a separate town with its own city charter. History The historical Praga was a small settlement located at the eastern bank of the Vistula river, directly opposite the towns of Old Warsaw and Mariensztat, both being parts of Warsaw now. First mentioned in 1432, it derived its name from the Polish verb ''prażyć'', meaning ''to burn'' or ''to roast'', as it occupied a forested area that was burnt out to make place for the village. Separated from Warsaw by a wide river, it developed independently of the nearby city, and on 10 February 1648 king Władysław IV of Poland granted Praga with a city charter. However, as it was mostly a suburb and most buildings were wooden, the town was repeatedly destroyed by fires, floods and foreign armies. Currently the only surviving historical monument from that epoch is the Church of Our Lady of Loreto. Alt ...
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Gas Turbine
A gas turbine, also called a combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part (known as the gas generator or core) and are, in the direction of flow: * a rotating gas compressor * a combustor * a compressor-driving turbine. Additional components have to be added to the gas generator to suit its application. Common to all is an air inlet but with different configurations to suit the requirements of marine use, land use or flight at speeds varying from stationary to supersonic. A propelling nozzle is added to produce thrust for flight. An extra turbine is added to drive a propeller ( turboprop) or ducted fan (turbofan) to reduce fuel consumption (by increasing propulsive efficiency) at subsonic flight speeds. An extra turbine is also required to drive a helicopter rotor or land-vehicle transmission ( turboshaft), marine propeller or electrical generator (power turbine). Grea ...
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Unmanned Aerial Vehicle
An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller and a system of communications with the UAV. The flight of UAVs may operate under remote control by a human operator, as remotely-piloted aircraft (RPA), or with various degrees of autonomy, such as autopilot assistance, up to fully autonomous aircraft that have no provision for human intervention. UAVs were originally developed through the twentieth century for military missions too "dull, dirty or dangerous" for humans, and by the twenty-first, they had become essential assets to most militaries. As control technologies improved and costs fell, their use expanded to many non-military applications.Hu, J.; Bhowmick, P.; Jang, I.; Arvin, F.; Lanzon, A.,A Decentralized Cluster Formation Containment Framework for Multirobot Systems IEEE T ...
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