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94-696: The Sikorsky CH-54 Tarhe is an American twin-engine heavy-lift helicopter designed by Sikorsky Aircraft for the United States Army . It is named after Tarhe , an 18th-century chief of the Wyandot Indian tribe whose nickname was "The Crane". The civilian version is the Sikorsky S-64 Skycrane . Work on what would become the CH-54 can be traced back to Sikorsky's earlier activities with "sky-crane" helicopters , particularly

188-616: 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

282-503: A blade designed for pushing. The word is sometimes used inaccurately for other heavy equipment such as a front-end loader designed for carrying rather than pushing material. The term originally referred only to the blade attachment but is now commonly applied to any crawler tractor with a front mounted blade. Typically, bulldozers are large and powerful tracked heavy equipment . The tracks give them excellent traction and mobility through very rough terrain. Wide tracks also help distribute

376-472: A brush rake for removing brush and roots. These attachments (home-built or built by small equipment manufacturers of attachments for wheeled and crawler tractors and trucks) appeared by 1929. Widespread acceptance of the bull-grader does not seem to appear before the mid-1930s. The addition of power down-force provided by hydraulic cylinders instead of just the weight of the blade made them the preferred excavation machine for large and small contractors alike by

470-444: 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

564-417: 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

658-588: A dozer blade-equipped tank or armoured personnel carrier. Some bulldozers have been fitted with armor by civilian operators to prevent bystanders or police from interfering with the work performed by the bulldozer, as in the case of strikes or demolition of condemned buildings. This has also been done by civilians with a dispute with the authorities, such as Marvin Heemeyer , who outfitted his Komatsu D355A bulldozer with homemade composite armor to then demolish government buildings. In recent years, innovations in

752-419: 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. Bulldozer Bulldozers are used heavily in large and small scale construction, road building, minings and quarrying , on farms, in heavy industry factories, and in military applications in both peace and wartime. The word "bulldozer" refers only to a motorized unit fitted with

846-463: 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

940-405: 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

1034-510: 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,

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1128-416: 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

1222-500: A manual transmission, such as the early Euclid C-6 and TC-12 or Model C Tournadozer, blade movement controlled by hydraulic cylinders or electric motors instead of early models' cable winch/brake, and automatic grade control. Hydraulic cylinders enabled the application of down force, more precise manipulation of the blade, and automated controls. In the very snowy winter of 1946–47 in the United Kingdom , in at least one case

1316-477: 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

1410-442: A remote cut-off village running out of food was supplied by a bulldozer towing a big sled carrying necessary supplies. A more recent innovation is the outfitting of bulldozers with GPS technology, such as manufactured by Topcon Positioning Systems, Inc., Trimble Inc , or Leica Geosystems , for precise grade control and (potentially) "stakeless" construction. As a response to the many, and often varying claims about these systems,

1504-494: 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

1598-441: 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

1692-417: 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

1786-429: 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

1880-460: 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

1974-452: 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

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2068-452: 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

2162-547: 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

2256-464: Is equipped with a replaceable tungsten steel alloy tip, known as a boot. Ripping can not only loosen soil (such as podzol hardpan) in agricultural and construction applications but break shaly rock or pavement into easily handled small rubble. A variant of the ripper is the stumpbuster, a single spike protruding horizontally used to split a tree stump. Bulldozers employed for combat-engineering roles are often fitted with armor to protect

2350-678: 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

2444-471: Is the all-wheel-drive wheeled bulldozer, which generally has four large rubber-tired wheels, hydraulically operated articulated steering , and a hydraulically actuated blade mounted forward of the articulation joint. The bulldozer's primary tools are the blade and the ripper: Bulldozer blades come in three types: Blades can be fitted straight across the frame, or at an angle. All can be lifted, some, with additional hydraulic cylinders, can be tilted to vary

2538-411: 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

2632-572: 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

2726-588: 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

2820-553: The CH-54A ; the first of these was officially accepted on 30 June 1963. Following a relatively brief period of testing and evaluation, the CH-54 was quickly put into active use in Vietnam. Early on, the type had demonstrated itself to possess unrivalled performance in some aspects. As of 2014, it continues to hold the helicopter record for highest altitude in level flight at 11,000 m (36,000 ft), which it set in 1971, as well at

2914-495: The Caterpillar D9 , was also used to clear mines and demolish enemy structures. Industry statistics based on 2010 production published by Off-Highway Research showed Shantui was the largest producer of bulldozers, making over 10,000 units that year or two in five crawler-type dozers made in the world. The next-largest producer by number of units is Caterpillar Inc., which produced 6,400 units. Komatsu introduced

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3008-527: 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

3102-473: The Type 73 or M8 tractor , to clear battlefield obstacles and prepare firing positions. Dozer blades may be mounted on main battle tanks to clear antitank obstacles or mines, and dig improvised shelters. A ripper is a long, claw-like shank that may be mounted singly or in multiples on the rear of a bulldozer to loosen hard and impacted materials. Usually a single shank is preferred for heavy ripping. The ripper

3196-499: 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

3290-471: The piston-engined Sikorsky S-60 of the late 1950s. Following the end of the Korean War , the United States Army sought to procure a successor to the Sikorsky CH-37 Mojave , an early piston-engined heavy lift helicopter; being aware of this need, Sikorsky were keen to fulfill it. The company was already working on the Sikorsky S-64 Skycrane , a civil-orientated heavy lift rotorcraft that

3384-754: The 1940s, by which time the term "bulldozer" referred to the entire machine and not just the attachment. Over the years, bulldozers got bigger and more powerful in response to the demand for equipment suited for ever larger earthworks . Firms such as Caterpillar , Komatsu , Clark Equipment Co , Case , Euclid , Allis Chalmers , Liebherr , LiuGong , Terex , Fiat-Allis , John Deere , Massey Ferguson , BEML , XGMA, and International Harvester manufactured large, tracked-type earthmoving machines. R.G. LeTourneau and Caterpillar manufactured large, rubber-tired bulldozers. Bulldozers grew more sophisticated as time passed. Improvements include drivetrains analogous to (in automobiles) an automatic transmission instead of

3478-448: The 1940s. To dig canals , raise earthen dams , and do other earth-moving jobs, these tractors were equipped with a large, thick, metal plate in front. (The blade got its curved shape later). In some early models, the driver sat on top in the open without a cabin. The three main types of bulldozer blades are a U-blade for pushing and carrying soil relatively long distances, a straight blade for "knocking down" and spreading piles of soil, and

3572-558: 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

3666-703: The CH-54 for most transport duties, eventually replacing it in Regular Army aviation units during the 1980s. Another heavy lift helicopter, the Sikorsky CH-53 Sea Stallion , had also been developed using many of the proven systems of the CH-54, including its engine, fuselage, and dynamic systems. The CH-54 was also operated by the Army National Guard , where it performed a variety of military and civilian missions. It participated in various humanitarian relief operations, including

3760-762: 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

3854-478: 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

Sikorsky CH-54 Tarhe - Misplaced Pages Continue

3948-565: The D575A in 1981, the D757A-2 in 1991, and the D575A-3 in 2002, which the company touts as the biggest bulldozer in the world. These appeared as early as 1929, but were known as "bull grader" blades, and the term "bulldozer blade" did not appear to come into widespread use until the mid-1930s. "Bulldozer" now refers to the whole machine, not just the attachment. In contemporary usage, "bulldozer"

4042-453: 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

4136-574: The Kellogg Report published in 2010 a detailed comparison of all the manufacturers' systems, evaluating more than 200 features for dozers alone. The best-known maker of bulldozers is Caterpillar. Komatsu , Liebherr , Case , Hitachi , Volvo , and John Deere are present-day competitors. Although these machines began as modified farm tractors, they became the mainstay for big civil construction projects, and found their way into use by military construction units worldwide. The best-known model,

4230-571: 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,

4324-550: 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

4418-583: The angle up to one side. Sometimes, a bulldozer is used to push or pull another piece of earth-moving equipment known as a " scraper " to increase productivity. The towed Fresno Scraper , invented in 1883 by James Porteous , was the first design to enable this to be done economically, removing the soil from an area being cut and depositing where needed as fill . Dozer blades with a reinforced center section for pushing are known as "bull blades". Dozer blades are added to combat engineering vehicles and other military equipment, such as artillery tractors such as

4512-466: 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

4606-435: 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

4700-482: The buffer zone. Some forces' engineer doctrines differentiate between a low-mobility armoured dozer (LMAD) and a high-mobility armoured dozer (HMAD). The LMAD is dependent on a flatbed to move it to its employment site, whereas the HMAD has a more robust engine and drive system designed to give it road mobility with a moderate range and speed. HMADs, however, normally lack the full cross-country mobility characteristics of

4794-677: 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

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4888-406: 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,

4982-412: The construction technology have made remote-controlled bulldozers a reality. Now, heavy machinery can be controlled from up to 1,000 feet away. This contributes to the safety of workers on the jobsite, keeping them at a secure distance from potentially dangerous jobs. The advancement and the ability to control the heavy machinery from afar provides workers with the sufficient control over the dozers to get

5076-470: 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

5170-564: The driver from firearms and debris, enabling bulldozers to operate in combat zones. The most widely documented use is the Israeli Military militarized Caterpillar D9 , for earth moving, clearing terrain obstacles, opening routes, and detonating explosive charges. The IDF used armoured bulldozers extensively during Operation Rainbow where they were used to uproot Gaza Strip smuggling tunnels and destroy residential neighbourhoods, water wells and pipes, and agricultural land to expand

5264-536: 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

5358-466: The end of the Cold War proved to be the death knell for the CH-54's military service; the final National Guard flight was conducted on 10 January 1993. Following their withdrawal from military use, many CH-54s were acquired by civilian operators and thus continued to be used in this new capacity. Of these, Erickson Air-Crane of Central Point, Oregon , operates the largest fleet of S-64 helicopters in

5452-407: The era was the incorporation of an automatic flight control system , effectively a fly-by-wire arrangement. This feature enabled the aft-facing crew member to control the rotorcraft's pitch , roll , and yaw with 10% control authority, along with an altitude-hold function; it was also praised for being relatively easy to fly under instrument flight rules (IFR). Considerable attention was paid to

5546-439: 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

5640-429: The fastest climb to 3,000, 6,000, and 9,000 m (10,000, 20,000, and 30,000 ft). On 20 April 1965, a CH-54A equipped with a people pod lifted 90 people, comprising its crew of three and 87 combat-equipped troops; this was the largest number of people to be lifted by a single helicopter at that time. The United States Army would ultimately procure 105 examples, which it operated under the designation of CH-54 Tarhe . It

5734-534: The first designs for the bulldozer. A replica is on display at the city park in Morrowville, Kansas , where the two built the first bulldozer. On December 18, 1923, Cummings and McLeod filed U.S. patent #1,522,378 that was later issued on January 6, 1925, for an "Attachment for Tractors." By the 1920s, tracked vehicles became common, particularly the Caterpillar 60 . Rubber-tired vehicles came into use in

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5828-486: 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

5922-734: The frontlines that several would come under fire from the North Vietnamese. One unusual use of the type came under the Combat Trap programme, which saw it drop 10,000 lb bombs, intended for clearing landing zones. One danger that its crews had to maintain awareness of was the strong downwash generated by the rotors; nearby tents were particularly at risk of being blown away. As a heavy transport helicopter, capable of retrieving numerous types of downed aircraft, it proved to be highly successful. The Tarhe can hold its cargo up and tight against its center spine to lessen drag and eliminate

6016-432: The fuselage's design, particularly to minimising weight and maintenance requirements. The landing gear was designed to kneel to make loading easier as well as to ease operations from sloped surfaces. From on onset, Sikorsky sought to enable the type to carry as diverse a range of cargoes as possible, leading to the incorporation of fitting for the carriage of barges and of a specially-designed multipurpose "people pod" that

6110-515: 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

6204-480: 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

6298-504: 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

6392-488: The job done. Though these machines are still in their early stages, many construction companies are using them successfully. The first bulldozers were adapted from Holt farm tractors that were used to plough fields. The versatility of tractors in soft ground for logging and road building contributed to the development of the armored tank in World War I . In 1923, farmer James Cummings and draftsman J. Earl McLeod made

6486-662: 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

6580-581: 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

6674-555: 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

6768-648: The military buffer zone along the Philadelphi Route . This use drew criticism against both the use and the suppliers of armoured bulldozers from human-rights organizations such as the EWASH-coalition and Human Rights Watch , the latter of whom urged Caterpillar to cease their sale of bulldozers to the IDF. The use of bulldozers was seen as necessary by Israeli authorities to uproot smuggling tunnels, destroy houses used by Palestinian gunmen, and expand

6862-485: 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

6956-601: 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

7050-464: 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

7144-508: The pendulum effect when flying forward, as well as winch vehicles up and down from a hovering position, so the helicopter can deploy loads while hovering. Due to budget cuts, the Heavy Lift Helicopter (HLH) program was canceled and the CH-54 was not upgraded with larger engines. The relatively small fleet proved costly to maintain, thus the tandem-rotor Boeing CH-47 Chinook , a rival heavy lift helicopter, gradually supplemented

7238-411: 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

7332-506: The rescuing of a whale in Alaska . Unusual payloads include whole antenna towers and log cabins ; another example was the use of a CH-54 to airlift air conditioners onto the roof of the Pentagon . Furthermore, it was commonly tasked with relocating non-airworthy or retired aircraft. Despite these atypical demands, the CH-54 achieved a strong safety record. The military cutbacks enacted at

7426-436: 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

7520-406: 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

7614-422: 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

7708-488: The saving of several hundred million dollars. In particular, those forces operating in and around the Demilitarized Zone (DMZ) between North Vietnam and South Vietnam were unable to rely on ground supply routes due to the unavoidable challenges posed by the local geography; instead, they were almost entirely dependent on air support provided by rotorcraft such as the CH-54. The type would operate so close to

7802-418: 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

7896-483: 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

7990-479: 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

8084-448: 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

8178-417: 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

8272-588: The vehicle's weight over a large area (decreasing ground pressure ), thus preventing it from sinking in sandy or muddy ground. Extra-wide tracks are known as swamp tracks or low ground pressure (lgp) tracks. Bulldozers have transmission systems designed to take advantage of the track system and provide excellent tractive force . These traits allow bulldozers to excel in road building , construction , mining , forestry , land clearing , infrastructure development, and any other projects requiring highly mobile, powerful, and stable earth-moving equipment. A variant

8366-572: 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

8460-579: The world under the name Erickson S-64 Aircrane . These can be equipped with water-dropping equipment (some also have foam/gel capability) for firefighting duties worldwide. After obtaining the type certificate and manufacturing rights in 1992, Erickson remains the manufacturer. A large number of surviving airframes exist in flyable condition as well as in museum collections worldwide. General characteristics Performance Related development Aircraft of comparable role, configuration, and era Related lists Helicopter A helicopter

8554-486: 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

8648-551: Was designed specifically for the purpose of carrying large payloads externally; the development of a military-configured derivative was viewed as a natural option. While Sikorsky were quick to recognise the advantages of adopting turboshaft propulsion, there were no suitable engines of that type initially available, thus it had to work with the American engine manufacturer Pratt and Whitney to modify their JT12 turbojet to produce one. One innovative feature for any helicopter of

8742-492: Was most prolifically used during the Vietnam War , typically to provide logistical support and heavy transport activities in aid of American ground troops. In the theater, CH-54s would routinely be used to reposition artillery pieces such as the M101 howitzer , and even airlift bulky payloads such as bulldozers and patrol boats . In terms of retrieved aircraft alone, in excess of 380 were reportedly recovered via CH-54, resulting in

8836-559: Was suited for use for personnel transport, paratroop operations, and even as a mobile hospital or mobile command post. On 9 May 1962, the first of three prototypes performed its maiden flight . It was subsequently tested by the US Army at Fort Benning while the other two underwent an evaluation in West Germany . During June 1963, it was announced that the US Army had placed an order for an initial six helicopters, designating it as

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