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53-579: The Sikorsky H-34 (company designation S-58 ) is an American piston-engined military utility helicopter originally designed by Sikorsky as an anti-submarine warfare (ASW) aircraft for the United States Navy . A development of the smaller Sikorsky H-19 Chickasaw (S-55), the H-34 was originally powered by a radial engine , but was later adapted to turbine power by the British licensee as

106-618: A Federal Aviation Administration type certificate for the conversion in April 1971. The conversion enhanced safety, allowing the aircraft to continue flight after an engine failure, and greatly improved its hot and high performance; whereas the R-1820 could only provide full power up to an altitude of 700 ft (210 m), the paired PT-6s provide full power up to 6,000 ft (1,800 m), and an S-58T can fly at maximum gross weight up to 5,000 ft (1,500 m). The type certificate for

159-553: A campervan -like conversion—featuring a built-in mini-kitchen and sleeping accommodations for four. Later in that decade, Orlando developed a larger version based on the S-58 and participated in a joint effort with popular American recreational vehicle (RV) manufacturer Winnebago Industries to market both aircraft as the Winnebago Heli-Home . The S-58 version featured a larger kitchenette, sleeping accommodations for six,

212-441: A crankshaft or by a swashplate or other suitable mechanism. A flywheel is often used to ensure smooth rotation or to store energy to carry the engine through an un-powered part of the cycle. The more cylinders a reciprocating engine has, generally, the more vibration-free (smoothly) it can operate. The power of a reciprocating engine is proportional to the volume of the combined pistons' displacement. A seal must be made between

265-459: A flywheel , the power from other pistons connected to the same shaft or (in a double acting cylinder ) by the same process acting on the other side of the piston. This is where the piston forms the smallest volume in the cylinder. In most types the expanded or " exhausted " gases are removed from the cylinder by this stroke . The exception is the Stirling engine , which repeatedly heats and cools

318-597: A capacity of 1,820 L (64 cu ft), making a total capacity of 25,480 L (900 cu ft) for the largest versions. For piston engines, an engine's capacity is the engine displacement , in other words the volume swept by all the pistons of an engine in a single movement. It is generally measured in litres (l) or cubic inches (c.i.d., cu in, or in ) for larger engines, and cubic centimetres (abbreviated cc) for smaller engines. All else being equal, engines with greater capacities are more powerful and consumption of fuel increases accordingly (although this

371-469: A cylinder to drive a reciprocating engine in a local-pollution-free urban vehicle. Torpedoes may use a working gas produced by high test peroxide or Otto fuel II , which pressurize without combustion. The 230 kg (510 lb) Mark 46 torpedo , for example, can travel 11 km (6.8 mi) underwater at 74 km/h (46 mph) fuelled by Otto fuel without oxidant . Quantum heat engines are devices that generate power from heat that flows from

424-418: A dozen cylinders or more. Cylinder capacities may range from 10 cm or less in model engines up to thousands of liters in ships' engines. The compression ratio affects the performance in most types of reciprocating engine. It is the ratio between the volume of the cylinder, when the piston is at the bottom of its stroke, and the volume when the piston is at the top of its stroke. The bore/stroke ratio

477-406: A hot to a cold reservoir. The mechanism of operation of the engine can be described by the laws of quantum mechanics . Quantum refrigerators are devices that consume power with the purpose to pump heat from a cold to a hot reservoir. In a reciprocating quantum heat engine, the working medium is a quantum system such as spin systems or a harmonic oscillator. The Carnot cycle and Otto cycle are

530-650: A large number of unusual varieties of piston engines that have various claimed advantages, many of which see little if any current use: Medical evacuation Medical evacuation , often shortened to medevac or medivac , is the timely and efficient movement and en route care provided by medical personnel to patients requiring evacuation or transport using medically equipped air ambulances , helicopters and other means of emergency transport including ground ambulance and maritime transfers. Examples include civilian EMS vehicles, civilian aeromedical helicopter services, and military air ambulances. This term also covers

583-400: A minibar, and an entertainment system; optional floats were offered for amphibious operations. The aircraft were featured in several American popular magazines and reportedly drew large crowds at RV shows and dealerships, but their high purchase price together with rising 1970s fuel prices resulted in very limited sales; production is not well documented but is estimated at only six or seven of

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636-572: A seal, and more heavily when higher combustion pressure moves around to their inner surfaces. It is common to classify such engines by the number and alignment of cylinders and total volume of displacement of gas by the pistons moving in the cylinders usually measured in cubic centimetres (cm or cc) or litres (l) or (L) (US: liter). For example, for internal combustion engines, single and two-cylinder designs are common in smaller vehicles such as motorcycles , while automobiles typically have between four and eight, and locomotives and ships may have

689-484: A sequence of strokes that admit and remove gases to and from the cylinder. These operations are repeated cyclically and an engine is said to be 2-stroke , 4-stroke or 6-stroke depending on the number of strokes it takes to complete a cycle. The most common type is 4-stroke, which has following cycles. The reciprocating engine developed in Europe during the 18th century, first as the atmospheric engine then later as

742-586: Is not to be confused with fuel efficiency , since high efficiency often requires a lean fuel-air ratio, and thus lower power density. A modern high-performance car engine makes in excess of 75 kW/L (1.65 hp/in ). Reciprocating engines that are powered by compressed air, steam or other hot gases are still used in some applications such as to drive many modern torpedoes or as pollution-free motive power. Most steam-driven applications use steam turbines , which are more efficient than piston engines. The French-designed FlowAIR vehicles use compressed air stored in

795-412: Is not true of every reciprocating engine), although power and fuel consumption are affected by many factors outside of engine displacement. Reciprocating engines can be characterized by their specific power , which is typically given in kilowatts per litre of engine displacement (in the U.S. also horsepower per cubic inch). The result offers an approximation of the peak power output of an engine. This

848-394: Is the fictitious pressure which would produce the same amount of net work that was produced during the power stroke cycle. This is shown by: where A p {\displaystyle A_{p}} is the total piston area of the engine, S {\displaystyle S} is the stroke length of the pistons, and V d {\displaystyle V_{d}}

901-459: Is the ratio of the diameter of the piston, or " bore ", to the length of travel within the cylinder, or "stroke". If this is around 1 the engine is said to be "square". If it is greater than 1, i.e. the bore is larger than the stroke, it is "oversquare". If it is less than 1, i.e. the stroke is larger than the bore, it is "undersquare". Cylinders may be aligned in line , in a V configuration , horizontally opposite each other, or radially around

954-425: Is the total displacement volume of the engine. Therefore: Whichever engine with the larger value of MEP produces more net work per cycle and performs more efficiently. In steam engines and internal combustion engines, valves are required to allow the entry and exit of gases at the correct times in the piston's cycle. These are worked by cams, eccentrics or cranks driven by the shaft of the engine. Early designs used

1007-423: Is then fed through one or more, increasingly larger bore cylinders successively, to extract power from the steam at increasingly lower pressures. These engines are called compound engines . Aside from looking at the power that the engine can produce, the mean effective pressure (MEP), can also be used in comparing the power output and performance of reciprocating engines of the same size. The mean effective pressure

1060-466: The Battle of Karameh , bringing Israeli troops in and out of the theatre as well as evacuating the wounded. This was the last operation of the S-58 as it was retired shortly later, having been replaced by the newer Bell 205 and Aérospatiale Super Frelon . The H-34's lift capacity was just sufficient to lift a Mercury space capsule. In 1961, the hatch of Mercury-Redstone 4 was prematurely detached and

1113-452: The D slide valve but this has been largely superseded by piston valve or poppet valve designs. In steam engines the point in the piston cycle at which the steam inlet valve closes is called the cutoff and this can often be controlled to adjust the torque supplied by the engine and improve efficiency. In some steam engines, the action of the valves can be replaced by an oscillating cylinder . Internal combustion engines operate through

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1166-702: The MedEvac role, while VIP transports carried significantly fewer people in much greater comfort. A total of 135 H-34s were built in the US and assembled by Sud-Aviation in France, 166 were produced under licence in France by Sud-Aviation for the French Air Force, Navy and Army Aviation (ALAT). The CH-34 was also built and developed under license from 1958 in the United Kingdom by Westland Aircraft as

1219-998: The United States Army 's aircraft designation system, also used by the United States Air Force , the helicopter was designated H-34 . The U.S. Army also applied the name Choctaw to the helicopter. In 1962, under the new unified DoD aircraft designation system , the Seabat was redesignated SH-34 , the Seahorse as the UH-34 , and the Choctaw as the CH-34 . Roles included utility transport, anti-submarine warfare, search and rescue , and VIP transport. In its standard configuration, transport versions could carry 12 to 16 troops, or eight stretcher cases if utilized in

1272-884: The Westland Wessex and by Sikorsky as the S-58T. The H-34 was also produced under license in France by Sud Aviation . The H-34 was one of the first successful military utility helicopters, serving on every continent with the armed forces of 25 countries. It saw combat in the Dominican Republic, Nicaragua, the Six-Day War , the Vietnam War , and the Algerian War , where the French Air Force used it to pioneer modern air assault tactics. It

1325-420: The steam engine . These were followed by the Stirling engine and internal combustion engine in the 19th century. Today the most common form of reciprocating engine is the internal combustion engine running on the combustion of petrol , diesel , liquefied petroleum gas (LPG) or compressed natural gas (CNG) and used to power motor vehicles and engine power plants . One notable reciprocating engine from

1378-515: The turboshaft engined Wessex which was used by the Royal Navy and Royal Air Force . The RN Wessex was fitted out with weapons and ASW equipment for use in an antisubmarine role. The RAF used the Wessex, with turboshaft engines, as an air/sea rescue helicopter and as troop transporter. Wessexes were also exported to other countries and produced for civilian use. Entering service in the 1950s,

1431-677: The 21st century, and was one of the longest serving and successful of the H-34 types. Used by RVNAF 219th Squadron to insert MACV-SOG reconnaissance teams into Laos. The H-34 was the primary RVNAF helicopter until replaced by the Bell UH-1 Huey. South Vietnam was taken over by North Vietnam, and the fate of these aircraft Israeli S-58s flew numerous combat missions after the end of the Six-Day War ; these missions were mainly against Palestinians infiltrating Israel or against their bases in Jordan. On 21 March 1968, various S-58s participated in

1484-772: The Army placing a contract in 1955 as the H-34, and the Marine Corp in 1957 (as the HUS-1). In 1962 these names were standardized to H-34, with additional prefixes and letters according to that U.S. designation system. Westland had already made a version of the predecessor of the S-58, the S-55 as the Westland Whirlwind , and they would go on to make a turbine powered version of the S-56 as the Westland Wessex . The Sikorsky S-58

1537-572: The H-34 by the late 20th century, the type remains in limited civil use in transport and external cargo lift roles, and some have been restored and flown as warbirds . In the early 1950s Sikorsky developed the S-58, an improved version of the S-55, which had enter service as the H-19 with the United States. The United States Navy issued a contract in 1952 for the S-58, entering service as the HUS-1,

1590-513: The S-55 and S-58 versions combined. Data from Jane's All the World's Aircraft 1958-59 General characteristics Performance Armament Related development Aircraft of comparable role, configuration, and era Related lists Reciprocating engine There may be one or more pistons. Each piston is inside a cylinder , into which a gas is introduced, either already under pressure (e.g. steam engine ), or heated inside

1643-516: The S-58T was sold to California Helicopter International in 1981. In the late 1980s and early 1990s, S-58T helicopters were operated by New York Helicopters in scheduled passenger airline service between JFK International Airport and East 34th Street Heliport , New York . In the early 1970s, Orlando Helicopter Airways developed a novel civil conversion of the S-55/H-19, the Heli-Camper ,

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1696-773: The U.S. Army's decision to deploy the CH-21 Shawnee to Vietnam instead of the CH-34, pending the introduction into widespread service of the Bell UH-1 Iroquois . U.S. Army H-34s did not participate in Vietnam, and did not fly in the assault helicopter role, but a quantity were supplied to the Republic of Vietnam Air Force (RVNAF). These saw little use due to a lack of spare parts and maintenance. Its higher availability and reliability due to its simplicity compared to

1749-732: The United States and locally assembled by Sud-Aviation . Later, a further 166 were domestically manufactured by Sud-Aviation; these were operated by the French Army Light Aviation ( Army ), French Naval Aviation ( Navy ) and Air force . The Wessex was used as an anti-submarine and utility helicopter with the Royal Navy and as a transport and search and rescue helicopter with the Royal Air Force. British Wessex saw action in several conflicts: Falklands, Oman, Borneo, Aden, etc. The twin-turbine Wessex served into

1802-489: The World War II era was the 28-cylinder, 3,500  hp (2,600 kW) Pratt & Whitney R-4360 Wasp Major radial engine. It powered the last generation of large piston-engined planes before jet engines and turboprops took over from 1944 onward. It had a total engine capacity of 71.5 L (4,360 cu in), and a high power-to-weight ratio . The largest reciprocating engine in production at present, but not

1855-643: The armed H-34s, known as "Stingers" were quickly phased out. The TK-1 kit would form the basis of the TK-2 kit used on the UH-1E helicopters of the USMC. An H-34 was featured in the famous early-Vietnam War Time-Life photo essay "One Ride With Yankee Papa 13", photographer Larry Burrows , which depicted stages of a disastrous combat mission in which several crew were wounded or killed. The H-34 remained in service with United States Army and Marine Corps aviation units into

1908-494: The capsule was filled with seawater. The extra weight was too much for the H-34 and the capsule, Liberty Bell 7 , was emergency released and sank in deep water, remaining on the ocean floor until 1999 . Sikorsky set up a production line in 1970 to remanufacture existing S-58 aircraft into the S-58T configuration, replacing the R-1820 engine with a pair of Pratt & Whitney Canada PT6T -3 Twin-Pac turboshafts ; Sikorsky obtained

1961-477: The crankshaft. Opposed-piston engines put two pistons working at opposite ends of the same cylinder and this has been extended into triangular arrangements such as the Napier Deltic . Some designs have set the cylinders in motion around the shaft, such as the rotary engine . In some steam engines, the cylinders may be of varying size with the smallest bore cylinder working the highest pressure steam. This

2014-430: The cylinder either by ignition of a fuel air mixture ( internal combustion engine ) or by contact with a hot heat exchanger in the cylinder ( Stirling engine ). The hot gases expand, pushing the piston to the bottom of the cylinder. This position is also known as the bottom dead center (BDC), or where the piston forms the largest volume in the cylinder. The piston is returned to the cylinder top (top dead center) (TDC) by

2067-490: The distinction of being the last piston-engined helicopter to be operated by the Marine Corps. On 3 September 1973, the last flight of a USMC UH-34 occurred as Bureau Number 147191 which had been formally assigned to Headquarters Squadron, FMF Pacific was flown from Quantico, Virginia to MCAS New River to be placed on static display. France purchased an initial batch of 134 Choctaws; these were shipped in kit-form from

2120-604: The largest ever built, is the Wärtsilä-Sulzer RTA96-C turbocharged two-stroke diesel engine of 2006 built by Wärtsilä . It is used to power the largest modern container ships such as the Emma Mærsk . It is five stories high (13.5 m or 44 ft), 27 m (89 ft) long, and weighs over 2,300 metric tons (2,535 short tons ; 2,264 long tons ) in its largest 14 cylinders version producing more than 84.42 MW (113,209 bhp). Each cylinder has

2173-540: The late 1960s; at this time it was also standard equipment in Marine Corps Reserve , Army Reserve and Army National Guard aviation units, eventually being replaced by the UH-1 Iroquois utility helicopter. Sikorsky terminated all production activities in 1968, a total of 1,821 having been built. All H-34 helicopters were retired from service in the U.S. military by the early 1970s; the type having

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2226-557: The newer helicopters led Marines to ask for it by name. The phrases "give me a HUS", "get me a HUS" and "cut me a HUS" entered the U.S. Marine Corps vernacular, being used even after the type was no longer in use to mean "help me out". USMC H-34s were also among the first helicopter gunships trialled in theatre, being fitted with the Temporary Kit-1 (TK-1) , comprising two M60C machine guns and two 19-shot 2.75 inch rocket pods. The operations were met with mixed enthusiasm, and

2279-410: The ones most studied. The quantum versions obey the laws of thermodynamics . In addition, these models can justify the assumptions of endoreversible thermodynamics . A theoretical study has shown that it is possible and practical to build a reciprocating engine that is composed of a single oscillating atom. This is an area for future research and could have applications in nanotechnology . There are

2332-505: The same sealed quantity of gas. The stroke is simply the distance between the TDC and the BDC, or the greatest distance that the piston can travel in one direction. In some designs the piston may be powered in both directions in the cylinder, in which case it is said to be double-acting . In most types, the linear movement of the piston is converted to a rotating movement via a connecting rod and

2385-407: The sliding piston and the walls of the cylinder so that the high pressure gas above the piston does not leak past it and reduce the efficiency of the engine. This seal is usually provided by one or more piston rings . These are rings made of a hard metal, and are sprung into a circular groove in the piston head. The rings fit closely in the groove and press lightly against the cylinder wall to form

2438-571: The transfer of patients from the battlefield to a treatment facility or from one treatment facility to another by medical personnel, such as from a local hospital to another medical facility which has adequate medical equipment. In Asia, according to Aeromedical Global (M) Sdn Bhd, medical evacuations via air ambulance can be performed via a single or dual stretched setup. According to patients medical condition, Emergency Air Ambulances will be equipped with relevant equipment (ventilators, Portable O2 Concentrator etc). The first medical transport by air

2491-571: The type served numerous roles in the late 20th century. The type was internationally and commercially. The helicopters used by the French Army Light Aviation (ALAT), including the Sikorsky H-34, aggregated over 190,000 flying hours in Algeria (over 87,000 for the H-21 alone) and helped to evacuate over 20,000 French combatants from the combat area, including nearly 2,200 at night. By the time

2544-465: The war in Algeria had ended, eight officers and 23 non-commissioned officers from ALAT had been killed. The use of armed helicopters during the Algerian War, coupled with helicopter transports which can insert troops into enemy territory, gave birth to some of the modern tactics of airmobile warfare . French evaluations on the reported ground fire vulnerabilities of the CH-34 may have influenced

2597-614: Was by 2nd Lt Carter Harman , in Japanese-held Burma , who had to make several hops to get his Sikorsky YR-4B to the 1st Air Commando Group 's secret airfield in enemy territory and then made four trips from there between April 25 and 26 to recover the American pilot and four injured British soldiers, one at a time. The first medivac under fire happened in Manila in 1945 when five pilots evacuated 75-80 soldiers one or two at

2650-520: Was developed as a lengthened and more powerful version of the Sikorsky Model S-55, or UH-19 Chickasaw , with a similar nose, but with a tail-dragger rear fuselage and landing gear, rather than the high-tail, 4-post pattern. It retained the nose-mounted radial reciprocating engine with the drive shaft passing through the cockpit placed high above the cargo compartment. The aircraft first flew on 8 March 1954. The first production aircraft

2703-487: Was ready in September and entered in service for the United States Navy initially designated HSS-1 Seabat (in its anti-submarine configuration) and HUS-1 Seahorse (in its utility transport configuration) under the U.S. Navy designation system for U.S. Navy, United States Marine Corps (USMC) and United States Coast Guard (USCG) aircraft. The U.S. Army and Marine Corps, respectively, ordered it in 1955 and 1957. Under

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2756-581: Was recorded in Serbia in the autumn of 1915 during the First World War . One of the ill soldiers in that first medical transport was Milan Rastislav Štefánik , a Slovak pilot-volunteer who was flown to safety by French aviator Louis Paulhan . The United States Army used this lifesaving technique in Burma toward the end of World War II with Sikorsky R-4B helicopters. The first helicopter rescue

2809-632: Was the last piston-engined helicopter to be operated by the United States Marine Corps (USMC), having been replaced by turbine-powered types such as the UH-1 Huey and CH-46 Sea Knight ; in the USMC, the H-34 was often called the "HUS" after its original designation in that service. A total of 2,340 H-34s were manufactured between 1953 and 1970, including the license productions in the UK and France. Although most military forces retired

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