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122-439: The AgustaWestland AW149 is a medium-lift multi-role military helicopter developed by AgustaWestland , now Leonardo , launched in 2006 and had its first flight in 2009. By 2014 it had received military flight certification, and it went on to enter production going into military service with Egypt and Thailand. It is also planned for Poland with a new PZL-Swidnik production line there that opened in 2024, and North Macedonia has

244-401: A Jesus nut ) for the rotor blades called the hub. The rotor blades are then attached to the hub, and the hub can have 10-20 times the drag of the blade. Main rotor systems are classified according to how the main rotor blades are attached and move relative to the main rotor hub. There are three basic classifications: rigid, semirigid, and fully articulated, although some modern rotor systems use

366-505: A fantail ), and MD Helicopters ' NOTAR . The number of rotors is also important, many helicopters have two rotors in a single line, and another configuration is 4 rotors. An example of two-blade rotor is the Bell 212 , and four blade version of this helicopter is the Bell 412 . An example of the effect of rotor blade number is the UH-72 ( EC145 variant ); the A model had four blades, but

488-616: A runway . In 1942, the Sikorsky R-4 became the first helicopter to reach full-scale production . 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 common helicopter configuration. However, twin-rotor helicopters (bicopters), in either tandem or transverse rotors configurations, are sometimes in use due to their greater payload capacity than

610-444: A collective input is made, all the blades change equally, and the result is the helicopter increasing or decreasing in altitude. A swashplate controls the collective and cyclic pitch of the main blades. The swashplate moves up and down, along the main shaft, to change the pitch of both blades. This causes the helicopter to push air downward or upward, depending on the angle of attack . The swashplate can also change its angle to move

732-401: A combination of these classifications. A rotor is a finely tuned rotating mass, and different subtle adjustments reduce vibrations at different airspeeds. The rotors are designed to operate at a fixed RPM (within a narrow range of a few percent), but a few experimental aircraft used variable speed rotors . Unlike the small diameter fans used in turbofan jet engines, the main rotor on

854-409: A common flapping or teetering hinge at the rotor shaft. This allows the blades to flap together in opposite motions like a seesaw . This underslinging of the blades below the teetering hinge, combined with an adequate dihedral or coning angle on the blades, minimizes variations in the radius of each blade's center of mass from the axis of rotation as the rotor turns, which in turn reduces the stress on

976-417: A constant altitude. The pedals serve the same function in both a helicopter and a fixed-wing aircraft, to maintain balanced flight. This is done by applying a pedal input in whichever direction is necessary to center the ball in the turn and bank indicator . Due to the operating characteristics of the helicopter—its ability to take off and land vertically, and to hover for extended periods of time, as well as

1098-468: A conventional design the rotor blades' angle of attack is reduced via a collective pitch control. Slowing the rotor instead can reduce drag during this phase of flight and thus improve fuel economy. Most helicopters have a single main rotor but require a separate rotor to overcome torque. This is accomplished through a variable-pitch antitorque rotor or tail rotor. This is the design that Igor Sikorsky settled on for his VS-300 helicopter, and it has become

1220-500: A degree of washout that reduces the lift generated at the tips, where the airflow is fastest and vortex generation would be a significant problem. Rotor blades are made out of various materials, including aluminium, composite structure, and steel or titanium , with abrasion shields along the leading edge. Rotorcraft blades are traditionally passive; however, some helicopters include active components on their blades. The Kaman K-MAX uses trailing edge flaps for blade pitch control and

1342-447: A direction opposite that of the main rotor's rotation, thereby countering the torque effect created by the main rotor. Tail rotors are simpler than main rotors since they require only collective changes in pitch to vary thrust. The pitch of the tail rotor blades is adjustable by the pilot via the anti-torque pedals, which also provide directional control by allowing the pilot to rotate the helicopter around its vertical axis, thereby changing

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1464-502: A ducted fan can have a smaller size than a conventional tail rotor. The Fenestron was used for the first time at the end of the 1960s on the second experimental model of Sud Aviation's SA 340 and produced on the later model Aérospatiale SA 341 Gazelle . Besides Eurocopter and its predecessors, a ducted fan tail rotor was also used on the canceled military helicopter project, the United States Army 's RAH-66 Comanche , as

1586-408: A few more flights and achieved a height of nearly 2.0 metres (6.5 ft), but it proved to be unstable and was abandoned. Main rotor The helicopter rotor is powered by the engine, through the transmission, to the rotating mast. The mast is a cylindrical metal shaft that extends upward from—and is driven by—the transmission. At the top of the mast is the attachment point (colloquially called

1708-593: A flexible hub, which allows for blade bending (flexing) without the need for bearings or hinges. These systems, called flexures , are usually constructed from composite material. Elastomeric bearings may also be used in place of conventional roller bearings . Elastomeric bearings are constructed from a rubber type material and provide limited movement that is perfectly suited for helicopter applications. Flexures and elastomeric bearings require no lubrication and, therefore, require less maintenance. They also absorb vibration, which means less fatigue and longer service life for

1830-463: A gift by their father, would inspire the Wright brothers to pursue the dream of flight. In 1861, the word "helicopter" was coined by Gustave de Ponton d'Amécourt , a French inventor who demonstrated a small steam-powered model. While celebrated as an innovative use of a new metal, aluminum, the model never lifted off the ground. D'Amecourt's linguistic contribution would survive to eventually describe

1952-405: A helicopter determines the size, function and capability of that helicopter design. The earliest helicopter engines were simple mechanical devices, such as rubber bands or spindles, which relegated the size of helicopters to toys and small models. For a half century before the first airplane flight, steam engines were used to forward the development of the understanding of helicopter aerodynamics, but

2074-402: A helicopter has a large diameter that lets it accelerate a large volume of air. This permits a lower downwash velocity for a given amount of thrust. As it is more efficient at low speeds to accelerate a large amount of air by a small degree than a small amount of air by a large degree, a low disk loading (thrust per disc area) greatly increases the aircraft's energy efficiency, and this reduces

2196-510: A helicopter powered by a gasoline engine with box kites attached to a mast by cables for a rotor, but it never flew. In 1906, two French brothers, Jacques and Louis Breguet , began experimenting with airfoils for helicopters. In 1907, those experiments resulted in the Gyroplane No.1 , possibly as the earliest known example of a quadcopter. Although there is some uncertainty about the date, sometime between 14 August and 29 September 1907,

2318-409: A helicopter. Twin rotors turn in opposite directions to counteract the torque effect on the aircraft without relying on an antitorque tail rotor. This lets the aircraft apply the power that would have driven a tail rotor to the main rotors, increasing lifting capacity. Primarily, three common configurations use the counterrotating effect on rotorcraft. Tandem rotors are two rotors—one mounted behind

2440-416: A helicopter. This is because a helicopter generates its own gusty air while in a hover, which acts against the fuselage and flight control surfaces. The result is constant control inputs and corrections by the pilot to keep the helicopter where it is required to be. Despite the complexity of the task, the control inputs in a hover are simple. The cyclic is used to eliminate drift in the horizontal plane, that

2562-417: A minimum. This stability is achieved by keeping the center of pressure virtually unchanged as the angle of attack changes. Center of pressure is the imaginary point on the chord line where the resultant of all aerodynamic forces are considered to be concentrated. Today, designers use thinner airfoils and obtain the required rigidity by using composite materials. Some airfoils are asymmetrical in design, meaning

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2684-629: A pending order. The aircraft the only contender for the British NMH procurement program in the 2020s. The AW149 began life as an all-new, military design. It was unveiled at the 2006 Farnborough Air Show , with a larger fuselage and more powerful engines compared to the AW139 , resulting in a greater cargo volume and payload carrying ability. On 13 November 2009, the first prototype conducted its first flight from AgustaWestland's Vergiate manufacturing facility in northern Italy . On 26 February 2011,

2806-477: A process of rebracketing , the word is often (erroneously, from an etymological point of view) perceived by English speakers as consisting of heli- and -copter , leading to words like helipad and quadcopter . English language nicknames for "helicopter" include "chopper", "copter", "heli", and "whirlybird". In the United States military, the common slang is "helo" pronounced /ˈhiː.loʊ/. A helicopter

2928-494: A rotor. The spinning creates lift, and the toy flies when released. The 4th-century AD Daoist book Baopuzi by Ge Hong ( 抱朴子 "Master who Embraces Simplicity") reportedly describes some of the ideas inherent to rotary wing aircraft. Designs similar to the Chinese helicopter toy appeared in some Renaissance paintings and other works. In the 18th and early 19th centuries Western scientists developed flying machines based on

3050-498: A simple rotor: Juan de la Cierva developed the fully articulating rotor for the autogyro . The basis of his design permitted successful helicopter development. In a fully articulated rotor system, each rotor blade is attached to the rotor hub through a series of hinges that let the blade move independently of the others. These rotor systems usually have three or more blades. The blades are allowed to flap, feather, and lead or lag independently of each other. The horizontal hinge, called

3172-441: A single main rotor, but torque created by its aerodynamic drag must be countered by an opposed torque. The design that Igor Sikorsky settled on for his VS-300 was a smaller tail rotor. The tail rotor pushes or pulls against the tail to counter the torque effect, and this has become the most common configuration for helicopter design, usually at the end of a tail boom . Some helicopters use other anti-torque controls instead of

3294-417: A state called translational lift which provides extra lift without increasing power. This state, most typically, occurs when the airspeed reaches approximately 16–24 knots (30–44 km/h; 18–28 mph), and may be necessary for a helicopter to obtain flight. In forward flight a helicopter's flight controls behave more like those of a fixed-wing aircraft. Applying forward pressure on the cyclic will cause

3416-474: A tandem configuration. An advantage of quad rotors on small aircraft such as drones is the opportunity for mechanical simplicity. A quadcopter using electric motors and fixed-pitch rotors has only four moving parts. Pitch, yaw and roll can be controlled by changing the relative lift of different rotor pairs without changing total lift. The two families of airfoils are Symmetrical blades are very stable, which helps keep blade twisting and flight control loads to

3538-460: A value of $ 1.85 billion (€1.76 billion). Delivery planned in years 2023-2029. In 2024, the Polish AW149 production line opened. Data from AgustaWestland. General characteristics Performance Armament Avionics Open architecture Related development Aircraft of comparable role, configuration, and era Related lists Helicopter A helicopter

3660-770: A version of the AW149, designated TUHP149 , as a candidate for the Turkish Utility Helicopter Program (TUHP) for the Turkish Armed Forces . The programme sought an initial batch of 109 helicopters worth $ 4 billion, prospective follow-on orders for subsequent batches may eventually rise to 300 rotorcraft. On 21 April 2011, the Turkish defence minister announced that the Sikorsky S-70i Black Hawk had been selected as

3782-429: Is a cylindrical metal shaft that extends upwards from the transmission. At the top of the mast is the attachment point for the rotor blades called the hub. Main rotor systems are classified according to how the rotor blades are attached and move relative to the hub. There are three basic types: hingeless, fully articulated, and teetering; although some modern rotor systems use a combination of these. Most helicopters have

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3904-460: 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 short take-off and landing ( STOL ) or short take-off and vertical landing ( STOVL ) aircraft cannot perform without

4026-452: Is a type of rotorcraft in which lift and thrust are supplied by one or more horizontally-spinning rotors. By contrast the autogyro (or gyroplane) and gyrodyne have a free-spinning rotor for all or part of the flight envelope, relying on a separate thrust system to propel the craft forwards, so that the airflow sets the rotor spinning to provide lift. The compound helicopter also has a separate thrust system, but continues to supply power to

4148-512: Is an increased mechanical complexity of the rotor system because it requires linkages and swashplates for two rotor systems. Also, because the rotors must rotate in opposite directions, the mast is more complex, and control linkages for pitch changes to the upper rotor system must pass through the lower rotor system. An example of coaxial design in a compound helicopter was the Sikorsky Skyraider X , which also had pusher prop at

4270-452: Is called an aerial crane . Aerial cranes are used to place heavy equipment, like radio transmission towers and large air conditioning units, on the tops of tall buildings, or when an item must be raised up in a remote area, such as a radio tower raised on the top of a hill or mountain. Helicopters are used as aerial cranes in the logging industry to lift trees out of terrain where vehicles cannot travel and where environmental concerns prohibit

4392-547: Is equipped to stabilize and provide limited medical treatment to a patient while in flight. The use of helicopters as air ambulances is often referred to as " MEDEVAC ", and patients are referred to as being "airlifted", or "medevaced". This use was pioneered in the Korean War , when time to reach a medical facility was reduced to three hours from the eight hours needed in World War II , and further reduced to two hours by

4514-470: Is simple and eliminates torque reaction, prototypes that have been built are less fuel efficient than conventional helicopters. Except for tip jets driven by unburnt compressed air, very high noise levels is the single most important reason why tip jet powered rotors have not gained wide acceptance. However, research into noise suppression is ongoing and may help make this system viable. There are several examples of tip jet powered rotorcraft. The Percival P.74

4636-452: Is that the center of pressure changes with changes in angle of attack. When the center of pressure lifting force is behind the pivot point on a rotor blade, it tends to cause the rotor disc to pitch up. As the angle of attack increases, the center of pressure moves forward. If it moves ahead of the pivot point, the pitch of the rotor disc decreases. Since the angle of attack of the rotor blades is constantly changing during each cycle of rotation,

4758-678: Is the Sud-Ouest Djinn , and an example of the hot tip jet helicopter is the YH-32 Hornet . Some radio-controlled helicopters and smaller, helicopter-type unmanned aerial vehicles , use electric motors or motorcycle engines. Radio-controlled helicopters may also have piston engines that use fuels other than gasoline, such as nitromethane . Some turbine engines commonly used in helicopters can also use biodiesel instead of jet fuel. There are also human-powered helicopters . A helicopter has four flight control inputs. These are

4880-483: Is the most common tandem rotor helicopter. Coaxial rotors are a pair of rotors mounted one above the other on the same shaft and turning in opposite directions. The advantage of the coaxial rotor is that, in forward flight, the lift provided by the advancing halves of each rotor compensates for the retreating half of the other, eliminating one of the key effects of dissymmetry of lift: retreating blade stall . However, other design considerations plague coaxial rotors. There

5002-411: Is to control forward and back, right and left. The collective is used to maintain altitude. The pedals are used to control nose direction or heading . It is the interaction of these controls that makes hovering so difficult, since an adjustment in any one control requires an adjustment of the other two, creating a cycle of constant correction. As a helicopter moves from hover to forward flight it enters

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5124-522: The Bell 205 and the Erickson S-64 Aircrane helitanker. Helicopters are used as air ambulances for emergency medical assistance in situations when an ambulance cannot easily or quickly reach the scene, or cannot transport the patient to a medical facility in time. Helicopters are also used when patients need to be transported between medical facilities and air transportation is the most practical method. An air ambulance helicopter

5246-588: The Bell 206 with 3,400. Most were in North America with 34.3% then in Europe with 28.0% followed by Asia-Pacific with 18.6%, Latin America with 11.6%, Africa with 5.3% and Middle East with 1.7%. The earliest references for vertical flight came from China. Since around 400 BC, Chinese children have played with bamboo flying toys (or Chinese top). This bamboo-copter is spun by rolling a stick attached to

5368-527: The Cornu helicopter which used two 6.1-metre (20 ft) counter-rotating rotors driven by a 24 hp (18 kW) Antoinette engine. On 13 November 1907, it lifted its inventor to 0.3 metres (1 ft) and remained aloft for 20 seconds. Even though this flight did not surpass the flight of the Gyroplane No. 1, it was reported to be the first truly free flight with a pilot. Cornu's helicopter completed

5490-681: The Focke-Achgelis Fa 223 , as well as the world's largest helicopter ever built, the Mil Mi-12 . It is also the configuration found on tiltrotors such as the Bell-Boeing V-22 Osprey and the AgustaWestland AW609 . A quad rotor or quadrotor comprises four rotors in an "X" configuration. Rotors to the left and right are in a transverse configuration while those in the front and to the rear are in

5612-636: The Hiller YH-32 Hornet was powered by ramjets mounted on the blade ends. As of 2010 , research into active blade control through trailing edge flaps is underway. Tips of some helicopter blades can be specially designed to reduce turbulence and noise and to provide more efficient flying. An example of such tips are the tips of the BERP rotors created during the British Experimental Rotor Programme. Description of

5734-470: The OH-58D Kiowa Warrior . This system is similar to the fully articulated type in that each blade has the ability to lead/lag and hunt independently of the other blades. The difference between a fully articulated system and soft-in-plane system is that the soft-in-plane system utilises a composite yoke. This yoke is attached to the mast and runs through the blade grips between the blades and

5856-499: The Vietnam War . In naval service a prime function of rescue helicopters is to promptly retrieve downed aircrew involved in crashes occurring upon launch or recovery aboard aircraft carriers. In past years this function was performed by destroyers escorting the carrier, but since then helicopters have proved vastly more effective. Police departments and other law enforcement agencies use helicopters to pursue suspects and patrol

5978-498: The flapping hinge , allows the blade to move up and down. This movement is called flapping and is designed to compensate for dissymmetry of lift . The flapping hinge may be located at varying distances from the rotor hub, and there may be more than one hinge. The vertical hinge, called the lead-lag hinge or drag hinge , allows the blade to move back and forth. This movement is called lead-lag, dragging, or hunting. Dampers are usually used to prevent excess back and forth movement around

6100-608: The 2 m/s for a civilian helicopter. The AW149 is being marketed as an alternative to the Sikorsky UH-60 Black Hawk family. Thailand has ordered 5 AW149 helicopters, and is the first export customer. The Italian Air Force considered it as a search and rescue helicopter, but chose the lighter AW139M instead. In April 2019, the Egyptian Navy ordered 24 AW149s with option for 10 more; first deliveries took place in late 2020. AgustaWestland submitted

6222-558: The Bambi bucket, are usually filled by submerging the bucket into lakes, rivers, reservoirs, or portable tanks. Tanks fitted onto helicopters are filled from a hose while the helicopter is on the ground or water is siphoned from lakes or reservoirs through a hanging snorkel as the helicopter hovers over the water source. Helitack helicopters are also used to deliver firefighters, who rappel down to inaccessible areas, and to resupply firefighters. Common firefighting helicopters include variants of

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6344-762: The Chinese top in a model consisting of contrarotating turkey flight feathers as rotor blades, and in 1784, demonstrated it to the French Academy of Sciences . Sir George Cayley , influenced by a childhood fascination with the Chinese flying top, developed a model of feathers, similar to that of Launoy and Bienvenu, but powered by rubber bands. By the end of the century, he had progressed to using sheets of tin for rotor blades and springs for power. His writings on his experiments and models would become influential on future aviation pioneers. Alphonse Pénaud would later develop coaxial rotor model helicopter toys in 1870, also powered by rubber bands. One of these toys, given as

6466-478: The Chinese toy. It was not until the early 1480s, when Italian polymath Leonardo da Vinci created a design for a machine that could be described as an " aerial screw ", that any recorded advancement was made towards vertical flight. His notes suggested that he built small flying models, but there were no indications for any provision to stop the rotor from making the craft rotate. As scientific knowledge increased and became more accepted, people continued to pursue

6588-568: The FANTAIL. NOTAR, an acronym for no ta il r otor , is a helicopter anti-torque system that eliminates the use of the tail rotor on a helicopter. Although the concept took some time to refine, the NOTAR system is simple in theory and provides antitorque the same way a wing develops lift by using the Coandă effect . A variable pitch fan is enclosed in the aft fuselage section immediately forward of

6710-453: The Gyroplane No. 1 lifted its pilot into the air about 0.6 metres (2 ft) for a minute. The Gyroplane No.   1 proved to be extremely unsteady and required a man at each corner of the airframe to hold it steady. For this reason, the flights of the Gyroplane No.   1 are considered to be the first manned flight of a helicopter, but not a free or untethered flight. That same year, fellow French inventor Paul Cornu designed and built

6832-571: The Martian atmosphere is 100 times thinner than Earth's, its two blades spin at close to 3,000 revolutions a minute, approximately 10 times faster than that of a terrestrial helicopter. In 2017, 926 civil helicopters were shipped for $ 3.68 billion, led by Airbus Helicopters with $ 1.87 billion for 369 rotorcraft, Leonardo Helicopters with $ 806 million for 102 (first three-quarters only), Bell Helicopter with $ 696 million for 132, then Robinson Helicopter with $ 161 million for 305. By October 2018,

6954-521: The U.S. and radio-control aeromodeler Dieter Schlüter in Germany, found that flight stability for helicopters could be achieved with a stabilizer bar, or flybar. The flybar has a weight or paddle (or both for added stability on smaller helicopters) at each end to maintain a constant plane of rotation. Through mechanical linkages, the stable rotation of the bar mixes with the swashplate movement to damp internal (steering) as well as external (wind) forces on

7076-554: The UH-72B was changed to five blades which reduced vibration. Other blade numbers are possible, for example, the CH-53K , a large military transport helicopter has a seven blade main rotor. The tail rotor is a smaller rotor mounted so that it rotates vertically or near-vertically at the end of the tail of a traditional single-rotor helicopter. The tail rotor's position and distance from the center of gravity allow it to develop thrust in

7198-511: The United States. Examples of hazards faced by Helicopters, includes ones common to aircraft such as bird-strikes , but also a number of others depending on the design of the helicopter and conditions. This includes but its not limited to: Dynamic rollover , Ground resonance , Loss of tail-rotor effectiveness , Retreating blade stall , Dynamic stall , Vortex ring state , Servo transparency , Mast bumping, and Tailstrike . Because

7320-424: The advantage of easy reconfiguration and fewer mechanical parts. Most helicopter rotors spin at constant speed. However slowing the rotor in some situations can bring benefits. As forward speed increases, the advancing rotor tip speed soon approaches the speed of sound . To reduce the problem, the speed of rotation may be slowed, allowing the helicopter to fly faster. To adjust the rotor lift at slower speeds, in

7442-550: The aircraft's handling properties under low airspeed conditions—it has proved advantageous to conduct tasks that were previously not possible with other aircraft, or were time- or work-intensive to accomplish on the ground. Today, helicopter uses include transportation of people and cargo, military uses, construction, firefighting, search and rescue , tourism , medical transport, law enforcement, agriculture, news and media , and aerial observation , among others. A helicopter used to carry loads connected to long cables or slings

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7564-426: The amount of airflow from the rotorwash. This is augmented by a direct jet thruster which also provides directional yaw control, with the presence of a fixed-surface empennage near the end of the tail, incorporating vertical stabilizers. Development of the NOTAR system dates back to 1975 when engineers at Hughes Helicopters began concept development work. In December 1981, Hughes flew an OH-6A fitted with NOTAR for

7686-466: The aviation industry; and the turboshaft engine for helicopter use, pioneered in December 1951 by the aforementioned Kaman K-225, finally gave helicopters an engine with a large amount of power and a low weight penalty. Turboshafts are also more reliable than piston engines, especially when producing the sustained high levels of power required by a helicopter. The turboshaft engine was able to be scaled to

7808-435: The blades angle forwards or backwards, or left and right, to make the helicopter move in those directions. The anti-torque pedals are located in the same position as the rudder pedals in a fixed-wing aircraft, and serve a similar purpose, namely to control the direction in which the nose of the aircraft is pointed. Application of the pedal in a given direction changes the pitch of the tail rotor blades, increasing or reducing

7930-467: The blades from lead and lag forces caused by the Coriolis effect . Secondary flapping hinges may also be used to provide sufficient flexibility to minimize bouncing. Feathering is accomplished by the feathering hinge at the blade root, which allows changes to the pitch angle of the blade. Modern rotor systems may use the combined principles of the rotor systems mentioned above. Some rotor hubs incorporate

8052-460: The blades tend to flap, feather, lead, and lag to a greater degree. Hexacopter is a popular configuration for unmanned drone helicopters, and ways to manage and improve the control of multirotor drones has been studied. The octocopter configuration is used notably in NASA's planned Dragonfly probe , designed to fly in the atmosphere of Saturn 's Moon Titan . A manned multirotor helicopter that

8174-451: The blades themselves compensate for the forces that previously required rugged hinges. The result is a rotor system that has less lag in control response because of the large hub moment typically generated. The rigid rotor system thus eliminates the danger of mast bumping inherent in semirigid rotors. The semirigid rotor can also be referred to as a teetering or seesaw rotor. This system is normally composed of two blades that meet just under

8296-677: The building of roads. These operations are referred to as longline because of the long, single sling line used to carry the load. In military service helicopters are often useful for delivery of outsized slung loads that would not fit inside ordinary cargo aircraft: artillery pieces, large machinery (field radars, communications gear, electrical generators), or pallets of bulk cargo. In military operations these payloads are often delivered to remote locations made inaccessible by mountainous or riverine terrain, or naval vessels at sea. In electronic news gathering , helicopters have provided aerial views of some major news stories, and have been doing so, from

8418-406: The cockpit from overhead. The control is called the cyclic because it changes cyclic pitch of the main blades. The result is to tilt the rotor disk in a particular direction, resulting in the helicopter moving in that direction. If the pilot pushes the cyclic forward, the rotor disk tilts forward, and the rotor produces a thrust in the forward direction. If the pilot pushes the cyclic to the side,

8540-470: The cyclic, the collective, the anti-torque pedals, and the throttle. The cyclic control is usually located between the pilot's legs and is commonly called the cyclic stick or just cyclic . On most helicopters, the cyclic is similar to a joystick. However, the Robinson R22 and Robinson R44 have a unique teetering bar cyclic control system and a few helicopters have a cyclic control that descends into

8662-468: The designs has not fully settled, with eVTOL being a popular name, also manned drone, or even flying car being used, or in certain cases Air Taxi. As an aircraft, the FAA has worked to refine the regulations surrounding eVTOL designs, which is oriented towards traditional Helicopters and airplanes, but in 2024 finalized airworthiness criteria as it resolves how to classify and certify these types of aircraft in

8784-423: The direction the craft is pointed. Fenestron and FANTAIL are trademarks for a ducted fan mounted at the end of the tail boom of the helicopter and used in place of a tail rotor. Ducted fans have between eight and eighteen blades arranged with irregular spacing so that the noise is distributed over different frequencies. The housing is integral with the aircraft skin and allows a high rotational speed; therefore,

8906-412: The drag hinge. The purpose of the drag hinge and dampers is to compensate for acceleration and deceleration caused by the difference in drag experienced by the advancing and retreating blades. Later models have switched from using traditional bearings to elastomeric bearings. Elastomeric bearings are naturally fail-safe and their wear is gradual and visible. The metal-to-metal contact of older bearings and

9028-536: The early 21st century, as well as recently weaponized utilities such as artillery spotting , aerial bombing and suicide attacks . The English word helicopter is adapted from the French word hélicoptère , coined by Gustave Ponton d'Amécourt in 1861, which originates from the Greek helix ( ἕλιξ ), genitive helikos (ἕλῐκος), "helix, spiral, whirl, convolution" and pteron ( πτερόν ) "wing". In

9150-466: The end of wings or outriggers perpendicular to the body of the aircraft. Similar to tandem rotors and intermeshing rotors, the transverse rotor also uses differential collective pitch. But like the intermeshing rotors, the transverse rotors use the concept for changes in the roll attitude of the rotorcraft. This configuration is found on two of the first viable helicopters, the Focke-Wulf Fw 61 and

9272-429: The engine turns the rotor creates a torque effect that causes the body of the helicopter to turn in the opposite direction of the rotor. To eliminate this effect, some sort of antitorque control must be used with a sufficient margin of power available to allow the helicopter to maintain its heading and provide yaw control. The three most common controls used today are the tail rotor, Eurocopter's Fenestron (also called

9394-439: The event was taken by Max Skladanowsky , but it remains lost . In 1885, Thomas Edison was given US$ 1,000 (equivalent to $ 34,000 today) by James Gordon Bennett, Jr. , to conduct experiments towards developing flight. Edison built a helicopter and used the paper for a stock ticker to create guncotton , with which he attempted to power an internal combustion engine. The helicopter was damaged by explosions and one of his workers

9516-486: The first half of the 20th century was that the amount of power produced by an engine was not able to overcome the engine's weight in vertical flight. This was overcome in early successful helicopters by using the smallest engines available. When the compact, flat engine was developed, the helicopter industry found a lighter-weight powerplant easily adapted to small helicopters, although radial engines continued to be used for larger helicopters. Turbine engines revolutionized

9638-436: The first rigid rotors, which was tested and developed on a series of helicopters in the 1960s and 1970s. In a rigid rotor system, each blade flaps and drags about flexible sections of the root. A rigid rotor system is mechanically simpler than a fully articulated rotor system. The aerodynamic and mechanical loads from flapping and lead/lag forces are accommodated through rotor blades flexing, rather than through hinges. By flexing,

9760-486: The first time. A more heavily modified prototype demonstrator first flew in March 1986 and successfully completed an advanced flight-test program, validating the system for future application in helicopter design. There are currently three production helicopters that incorporate the NOTAR design, all produced by MD Helicopters. This antitorque design also improves safety by eliminating the possibility of personnel walking into

9882-402: The front rotor tilts right and the rear rotor tilts left. To pivot left, the front rotor tilts left and the rear rotor tilts right. All rotor power contributes to lift, and it is simpler to handle changes in the center of gravity fore-aft. However, it requires the expense of two large rotors rather than the more common one large main rotor and a much smaller tail rotor. The Boeing CH-47 Chinook

10004-426: The fuel use and permits reasonable range. The hover efficiency ("figure of merit") of a typical helicopter is around 60%. The inner third length of a rotor blade contributes very little to lift due to its low airspeed. The blades of a helicopter are long, narrow airfoils with a high aspect ratio , a shape that minimizes drag from tip vortices (see the wings of a glider for comparison). They generally contain

10126-470: The helicopter components. Controls vary the pitch of the main rotor blades cyclically throughout rotation. The pilot uses this to control the direction of the rotor thrust vector , which defines the part of the rotor disc where the maximum thrust develops. Collective pitch varies the magnitude of rotor thrust by increasing or decreasing thrust over the whole rotor disc at the same time. These blade pitch variations are controlled by tilting, raising, or lowering

10248-515: The high operating cost of helicopters cost-effective in ensuring that oil platforms continue to operate. Various companies specialize in this type of operation. NASA developed Ingenuity , a 1.8 kg (4.0 lb) helicopter used to survey Mars (along with a rover). It began service in February 2021 and was retired due to sustained rotor blade damage in January 2024 after 73 sorties. As

10370-480: The idea of vertical flight. In July 1754, Russian Mikhail Lomonosov had developed a small coaxial modeled after the Chinese top but powered by a wound-up spring device and demonstrated it to the Russian Academy of Sciences . It was powered by a spring, and was suggested as a method to lift meteorological instruments. In 1783, Christian de Launoy , and his mechanic , Bienvenu, used a coaxial version of

10492-504: The in-service and stored helicopter fleet of 38,570 with civil or government operators was led Robinson Helicopter with 24.7% followed by Airbus Helicopters with 24.4%, then Bell with 20.5 and Leonardo with 8.4%, Russian Helicopters with 7.7%, Sikorsky Aircraft with 7.2%, MD Helicopters with 3.4% and other with 2.2%. The most widespread model is the piston Robinson R44 with 5,600, then the H125/ AS350 with 3,600 units, followed by

10614-429: The individual blades through pitch links and pitch horns. The non-rotating plate is connected to links that are manipulated by pilot controls—specifically, the collective and cyclic controls. The swash plate can shift vertically and tilt. Through shifting and tilting, the non-rotating plate controls the rotating plate, which in turn controls the individual blade pitch. A number of engineers, among them Arthur M. Young in

10736-662: The lack of an airstrip would make transport via fixed-wing aircraft impossible. The use of transport helicopters to deliver troops as an attack force on an objective is referred to as " air assault ". Unmanned aerial systems (UAS) helicopter systems of varying sizes are developed by companies for military reconnaissance and surveillance duties. Naval forces also use helicopters equipped with dipping sonar for anti-submarine warfare , since they can operate from small ships. Oil companies charter helicopters to move workers and parts quickly to remote drilling sites located at sea or in remote locations. The speed advantage over boats makes

10858-581: The late 1960s. Helicopters have also been used in films, both in front and behind the camera. The largest single non-combat helicopter operation in history was the disaster management operation following the 1986 Chernobyl nuclear disaster . Hundreds of pilots were involved in airdrop and observation missions, making dozens of sorties a day for several months. " Helitack " is the use of helicopters to combat wildland fires . The helicopters are used for aerial firefighting (water bombing) and may be fitted with tanks or carry helibuckets . Helibuckets, such as

10980-555: The limited power did not allow for manned flight. The introduction of the internal combustion engine at the end of the 19th century became the watershed for helicopter development as engines began to be developed and produced that were powerful enough to allow for helicopters able to lift humans. Early helicopter designs utilized custom-built engines or rotary engines designed for airplanes, but these were soon replaced by more powerful automobile engines and radial engines . The single, most-limiting factor of helicopter development during

11102-485: The monorotor design, and coaxial-rotor , tiltrotor and compound helicopters are also all flying today. Four-rotor helicopters ( quadcopters ) were pioneered as early as 1907 in France, and along with other types of multicopters , have been developed mainly for specialized applications such as commercial unmanned aerial vehicles (drones) due to the rapid expansion of drone racing and aerial photography markets in

11224-495: The most unusual design of this type was the Rotary Rocket Roton ATV , which was originally envisioned to take off using a rocket-tipped rotor. The French Sud-Ouest Djinn used unburnt compressed air to drive the rotor, which minimized noise and helped it become the only tip jet driven rotor helicopter to enter production. The Hughes XH-17 had a tip jet-driven rotor, which remains the largest rotor ever fitted to

11346-601: The nearby park, the Parco Forlanini. Emmanuel Dieuaide's steam-powered design featured counter-rotating rotors powered through a hose from a boiler on the ground. In 1887 Parisian inventor, Gustave Trouvé , built and flew a tethered electric model helicopter. In July 1901, the maiden flight of Hermann Ganswindt 's helicopter took place in Berlin-Schöneberg; this was probably the first heavier-than-air motor-driven flight carrying humans. A movie covering

11468-452: The need for lubrication is eliminated in this design. The third hinge in the fully articulated system is called the feathering hinge about the feathering axis. This hinge is responsible for the change in pitch of rotor blades excited via pilot input to the collective or cyclic. A variation of the fully articulated system is the soft-in-plane rotor system. This type of rotor can be found on several aircraft produced by Bell Helicopter, such as

11590-464: The nose to pitch down, with a resultant increase in airspeed and loss of altitude. Aft cyclic will cause the nose to pitch up, slowing the helicopter and causing it to climb. Increasing collective (power) while maintaining a constant airspeed will induce a climb while decreasing collective will cause a descent. Coordinating these two inputs, down collective plus aft cyclic or up collective plus forward cyclic, will result in airspeed changes while maintaining

11712-495: The other. Coaxial rotors are two rotors mounted one above the other on the same axis. Intermeshing rotors are two rotors mounted close to each other at a sufficient angle to let the rotors intermesh over the top of the aircraft. Another configuration—found on tiltrotors and some early helicopters—is called transverse rotors, where a pair of rotors are mounted at each end of a wing-type structure or outrigger. Tandem rotors are two horizontal main rotor assemblies mounted one behind

11834-480: The other. Tandem rotors achieve pitch attitude changes to accelerate and decelerate the helicopter through a process called cyclic pitch. To pitch forward and accelerate, both rotors increase the pitch at the rear and reduce the pitch at the front (cyclic) keeping torque the same on both rotors, flying sideways is achieved by increasing the pitch on one side and reducing pitch on the other. Yaw control develops through opposing cyclic pitch in each rotor. To pivot right,

11956-411: The power normally required to be diverted for the tail rotor to be applied fully to the main rotors, increasing the aircraft's power efficiency and lifting capacity. There are several common configurations that use the counter-rotating effect to benefit the rotorcraft: Tip jet designs let the rotor push itself through the air and avoid generating torque. The number, size and type of engine(s) used on

12078-585: The rear. Intermeshing rotors on a helicopter are a set of two rotors turning in opposite directions with each rotor mast mounted on the helicopter with a slight angle to the other so that the blades intermesh without colliding. This configuration is sometimes referred to as a synchropter. Intermeshing rotors have high stability and powerful lifting capability. The arrangement was pioneered in Nazi Germany in 1939 with Anton Flettner 's successful Flettner Fl 265 design, and later placed in limited production as

12200-406: The recognized convention for helicopter design, although designs do vary. When viewed from above, most American helicopter rotors turn counter-clockwise; French and Russian helicopters turn clockwise. Another type of rotorcraft is the tiltrotor , which has many similarities to helicopter main rotors when in mode of powered lift . With a single main rotor helicopter, the creation of torque as

12322-436: The rotor disk tilts to that side and produces thrust in that direction, causing the helicopter to hover sideways. The collective pitch control or collective is located on the left side of the pilot's seat with a settable friction control to prevent inadvertent movement. The collective changes the pitch angle of all the main rotor blades collectively (i.e. all at the same time) and independently of their position. Therefore, if

12444-406: The rotor in cruise, which allows its rotation to be slowed down , thus increasing the maximum speed of the aircraft. The Lockheed AH-56A Cheyenne diverted up to 90% of its engine power to a pusher propeller during forward flight. There are three basic flight conditions for a helicopter: hover, forward flight and the transition between the two. Hovering is the most challenging part of flying

12566-422: The rotor throughout normal flight. The rotor system, or more simply rotor , is the rotating part of a helicopter that generates lift . A rotor system may be mounted horizontally, as main rotors are, providing lift vertically, or it may be mounted vertically, such as a tail rotor, to provide horizontal thrust to counteract torque from the main rotors. The rotor consists of a mast, hub and rotor blades. The mast

12688-455: The rotor. The Lockheed rotor system used a control gyro, similar in principle to that of the Bell stabilizer bar, but designed for both hands-off stability and rapid control response of the hingeless rotor system. In fly-by-wire helicopters or Remote Control (RC) models, a microcontroller with gyroscope sensors and a Venturi sensor can replace the stabilizer. This flybar-less design has

12810-417: The rotor. This makes it easier for the pilot to maintain control of the aircraft. Stanley Hiller arrived at a similar method to improve stability by adding short stubby airfoils, or paddles, at each end. However, Hiller's "Rotormatic" system also delivered cyclic control inputs to the main rotor as a sort of control rotor, and the paddles provided the added stability by damping the effects of external forces on

12932-457: The second prototype, the first with production model engines, made its first flight from Vergiate. On 20 June 2011 AgustaWestland announced the AW189 , a civilian development of the AW149, for service in 2013. Military certification for the AW149 was announced by Finmeccanica at the 2014 Farnborough airshow. The landing gear can sustain a touchdown with a sink speed of 9.5 m/s, compared with

13054-403: The shear bearing inside the grip. This yoke does transfer some movement of one blade to another, usually opposing blades. While this is not fully articulated, the flight characteristics are very similar and maintenance time and cost are reduced. The term rigid rotor usually refers to a hingeless rotor system with blades flexibly attached to the hub. Irv Culver of Lockheed developed one of

13176-418: The size of the helicopter being designed, so that all but the lightest of helicopter models are powered by turbine engines today. Special jet engines developed to drive the rotor from the rotor tips are referred to as tip jets . Tip jets powered by a remote compressor are referred to as cold tip jets, while those powered by combustion exhaust are referred to as hot tip jets. An example of a cold jet helicopter

13298-483: The skies. Since helicopters can achieve a unique aerial view, they are often used in conjunction with police on the ground to report on suspects' locations and movements. They are often mounted with lighting and heat-sensing equipment for night pursuits. Military forces use attack helicopters to conduct aerial attacks on ground targets. Such helicopters are mounted with missile launchers and miniguns . Transport helicopters are used to ferry troops and supplies where

13420-673: The successful Flettner Fl 282 Kolibri , used by the German Kriegsmarine in small numbers (24 airframes produced) as an experimental light anti-submarine warfare helicopter. During the Cold War , an American company, Kaman Aircraft , produced the HH-43 Huskie for USAF firefighting and rescue missions. The latest Kaman model, the Kaman K-MAX , is a dedicated sky crane design. Transverse rotors are mounted on

13542-410: The swash plate with the flight controls. The vast majority of helicopters maintain a constant rotor speed (RPM) during flight, leaving the angle of attack of the blades as the sole means of adjusting thrust from the rotor. The swash plate is two concentric disks or plates. One plate rotates with the mast, connected by idle links, while the other does not rotate. The rotating plate is also connected to

13664-438: The tail boom and is driven by the main rotor transmission. To provide the sideways force to counteract the clockwise torque produced by a counterclockwise-spinning main rotor (as seen from above the main rotor), the variable-pitch fan forces low pressure air through two slots on the right side of the tailboom, causing the downwash from the main rotor to hug the tailboom, producing lift and thus a measure of antitorque proportional to

13786-428: The tail rotor, such as the ducted fan (called Fenestron or FANTAIL ) and NOTAR . NOTAR provides anti-torque similar to the way a wing develops lift through the use of the Coandă effect on the tail boom. The use of two or more horizontal rotors turning in opposite directions is another configuration used to counteract the effects of torque on the aircraft without relying on an anti-torque tail rotor. This allows

13908-498: The tail rotor. A predecessor (of sorts) to this system existed in the form of Great Britain's Cierva W.9 helicopter, a late 1940s aircraft using the cooling fan from its piston engine to push air through a nozzle built into the tailboom to counteract rotor-torque. The main rotor may be driven by tip jets. Such a system may be powered by high pressure air provided by a compressor. The air may or may not be mixed with fuel and burnt in ram-jets, pulse-jets, or rockets. Though this method

14030-448: The throttle is to maintain enough engine power to keep the rotor RPM within allowable limits so that the rotor produces enough lift for flight. In single-engine helicopters, the throttle control is a motorcycle-style twist grip mounted on the collective control, while dual-engine helicopters have a power lever for each engine. A compound helicopter has an additional system for thrust and, typically, small stub fixed wings . This offloads

14152-417: The thrust produced by the tail rotor and causing the nose to yaw in the direction of the applied pedal. The pedals mechanically change the pitch of the tail rotor altering the amount of thrust produced. Helicopter rotors are designed to operate in a narrow range of RPM . The throttle controls the power produced by the engine, which is connected to the rotor by a fixed ratio transmission. The purpose of

14274-405: The upper and lower surfaces do not have the same camber. Normally these airfoils would not be as stable, but this can be corrected by bending the trailing edge to produce the same characteristics as symmetrical airfoils. This is called "reflexing." Using this type of rotor blade allows the rotor system to operate at higher forward speeds. One of the reasons an asymmetrical rotor blade is not as stable

14396-572: The vertical flight he had envisioned. Steam power was popular with other inventors as well. In 1877, the Italian engineer, inventor and aeronautical pioneer Enrico Forlanini developed an unmanned helicopter powered by a steam engine . It rose to a height of 13 meters (43 feet), where it remained for 20 seconds, after a vertical take-off from a park in Milan . Milan has dedicated its city airport to Enrico Forlanini, also named Linate Airport , as well as

14518-513: The winner. Leonardo has proposed the AW149 for the UK's New Medium Helicopter programme, which aims to replace the RAF's Puma helicopters, with production to be at Leonardo's Yeovil factory if the bid is successful. In June 2022 Polish defence minister said Poland would order 32 AW149 helicopters, with production to be at Leonardo's PZL Świdnik factory. The contract was signed on 1 July 2022, and has

14640-486: Was badly burned. Edison reported that it would take a motor with a ratio of three to four pounds per horsepower produced to be successful, based on his experiments. Ján Bahýľ , a Slovak inventor, adapted the internal combustion engine to power his helicopter model that reached a height of 0.5 meters (1.6 feet) in 1901. On 5 May 1905, his helicopter reached 4 meters (13 feet) in altitude and flew for over 1,500 meters (4,900 feet). In 1908, Edison patented his own design for

14762-433: Was flying in the 2010s had 18 electrically powered rotors; the single seat aircraft is powered by batteries. The first aerobatic manned drone, as this type of electrically powered multi-rotor helicopter is known, had 12 rotors and could carry 1-2 people. Manned drones or eVTOL as they are called typically multirotor designs powered by batteries gained increasing popularity and designs in the 2020s. The naming of some of

14884-418: Was under-powered and could not fly. The Hiller YH-32 Hornet had good lifting capability but performed poorly otherwise. Other aircraft used auxiliary thrust for translational flight so that the tip jets could be shut down while the rotor autorotated. The experimental Fairey Jet Gyrodyne , 48-seat Fairey Rotodyne passenger prototypes and McDonnell XV-1 compound gyroplanes flew well using this method. Perhaps

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