An amphibious helicopter is a helicopter that is intended to land on and take off from both land and water. Amphibious helicopters are used for a variety of specialized purposes including air-sea rescue, marine salvage and oceanography, in addition to other tasks that can be accomplished with any non-amphibious helicopter. An amphibious helicopter can be designed with a waterproof or water-resistant hull like a flying boat or it can be fitted with utility floats in the same manner as a floatplane. [1]
Helicopters have taken a primary role in air-sea rescue since their introduction in the 1940s. [2] Helicopters can fly in rougher weather than fixed-wing aircraft, have the advantage of VTOL, and can deliver injured passengers directly to hospitals or other emergency facilities (requiring no runway or airport). A practical amphibious helicopter first appeared in 1941 [3] and the water-landing feature soon proved its worth. Non-amphibious helicopters were required to hover above the scene of a water accident and utilize a hoist but amphibious helicopters were capable of setting down on the water to effect a rescue more directly. [4]
In 1941, Igor Sikorsky fitted utility floats (also called pontoons) to the Vought-Sikorsky VS-300, making the first practical amphibious helicopter. [3] [5] In the 1940s and 1950s, some models of helicopter such as the Bell 47 and 48 and the Sikorsky R-4 and R-6 [6] were fitted with utility floats so that they could rest on both water and land. [7]
Pontoons can be filled with air or they can be utilized for storage of fuel or supplies. In 1949, Sikorsky produced the H-5H with both wheels and pontoons. [8]
The Sikorsky S-62 Seaguard was the first amphibious helicopter made with a flying boat hull—the prototype flew in 1958. [9] Utilizing many components of the earlier S-55, the S-62 proved the idea, and Sikorsky flew their S-61 Sea King prototype in 1959 for the U.S. Navy, a model intended for anti-submarine warfare. [10] Both the S-62 and S-61 were ready for delivery in 1961. Sikorsky produced 1100 S-61s, including some that were not watertight: a longer cargo-carrying version was given rear doors and a ramp. Sikorsky licensed other manufacturers such as Agusta, Mitsubishi and Westland to produce variants of the S-61. [11]
Amphibious helicopters came into their own in the 1960s when robust boat-hulled designs were produced in quantity for military and civilian operators. Amphibious helicopters paid dividends for rescue personnel who enjoyed greater safety and success during operations. [4] Overwater operations that used non-amphibious helicopters relied to a higher degree on hoists, rescue baskets, and rescue swimmers. [4] Nevertheless, beginning in the 1970s, amphibious models were steadily replaced by helicopter models unable to land on water, because of high amphibious aircraft development costs. [4] The last amphibious helicopter model used by the United States Coast Guard was the Sikorsky HH-3F Pelican, retired in 1994. [12]
Resting on the surface of the water with the rotor stopped, in conditions of brisk wind and mounting surface waves, a boat-hulled helicopter with stabilizing floats on either side is less likely to remain upright than a non-boat helicopter fitted with utility pontoons. [13] Difficulty in lifting off can be encountered, especially when heavily loaded or in increasing seas.
The Canadian Forces developed a technique called water bird for landing their CH-124 Sea Kings in water.
Helicopters can be designed to withstand limited contact with the surface of a body of water. The 1958 Vertol HUP-2 was an amphibious development of the twin-rotor Piasecki H-25 which strengthened its hull and replaced lower nose windows with tough aluminum. [14] The HUP-2 was provided with a pair of stabilizing outrigger floats positioned amidships. The HUP-2 was able to taxi forward or backward on water, regardless of wind direction. [15]
The CH-46 Sea Knight and its Canadian variant, the CH-113 Labrador, can land on water and rest for up to two hours [16] in calm water. [17] The rear sponsons hold two of the three landing gear units as well as self-sealing fuel tanks. The helicopter began service with the United States Marine Corps in 1962, [16] and with the Canadian military in 1963, and is used to carry cargo and combat troops.
The Boeing CH-47 Chinook was made sufficiently watertight to allow it to land on water for a short time in carrying out covert operations and special military missions. Buoyancy was increased with sealed compartments inside sponsons which extended most of the way along each side of the fuselage. For extended water usage, Boeing offered a kit to enhance its water resistance. [18] The Sikorsky CH-53 Sea Stallion, first introduced in 1966, is also capable of limited water landing.
Amphibious helicopters have been used in a variety of roles, including air-sea rescue, anti-submarine warfare, supporting special forces operations, and transporting the US president. [19]
The Boeing Vertol CH-46 Sea Knight is an American medium-lift tandem-rotor transport helicopter powered by twin turboshaft engines. It was designed by Vertol and manufactured by Boeing Vertol following Vertol's acquisition by Boeing.
The Sikorsky SH-3 Sea King is an American twin-engined anti-submarine warfare (ASW) helicopter designed and built by Sikorsky Aircraft. A landmark design, it was one of the first ASW rotorcraft to use turboshaft engines.
Sikorsky Aircraft is an American aircraft manufacturer based in Stratford, Connecticut. It was established by the Russian aviation pioneer Igor Sikorsky in 1923, and was among the first companies to manufacture helicopters for civilian and military use. It also produced seaplanes for passenger transport and surface vehicles such as trains and boats.
A flying boat is a type of seaplane with a hull, allowing it to land on water. It differs from a floatplane in having a fuselage that is purpose-designed for flotation, while floatplanes rely on fuselage-mounted floats for buoyancy.
A seaplane is a powered fixed-wing aircraft capable of taking off and landing (alighting) on water. Seaplanes are usually divided into two categories based on their technological characteristics: floatplanes and flying boats; the latter are generally far larger and can carry far more. Seaplanes that can also take off and land on airfields are in a subclass called amphibious aircraft, or amphibians. Seaplanes were sometimes called hydroplanes, but currently this term applies instead to motor-powered watercraft that use the technique of hydrodynamic lift to skim the surface of water when running at speed.
An amphibious aircraft, or amphibian, is an aircraft that can take off and land on both solid ground and water. These aircraft are typically fixed-wing, though amphibious helicopters do exist as well. Fixed-wing amphibious aircraft are seaplanes which are equipped with retractable wheels, at the expense of extra weight and complexity, plus diminished range and fuel economy compared with planes designed specifically for land-only or water-only operation.
The AgustaWestland AW101 is a medium-lift helicopter in military and civil use. First flown in 1987, it was developed by a joint venture between Westland Helicopters in the United Kingdom and Agusta in Italy in response to national requirements for a modern naval utility helicopter. Several operators, including the armed forces of Britain, Denmark, and Portugal, use the name Merlin for their AW101 aircraft. It is manufactured at factories in Yeovil, England, and Vergiate, Italy. Licensed assembly work has also taken place in Japan and the United States.
The Sikorsky CH-53E Super Stallion is a heavy lift helicopter operated by the United States military. As the Sikorsky S-80, it was developed from the CH-53 Sea Stallion, mainly by adding a third engine, adding a seventh blade to the main rotor, and canting the tail rotor 20°. It was built by Sikorsky Aircraft for the United States Marine Corps. Developed in the 1970s, it entered service in 1981, and is planned to be in service into the 2030s. It is one of the largest helicopters, and military helicopters in service, and is operated from U.S. Navy ships or from land.
The Sikorsky S-76 is a medium-size commercial utility helicopter designed and produced by the American helicopter manufacturer Sikorsky Aircraft. It is the company's first helicopter specifically developed for the civilian market.
The Sikorsky CH-124 Sea King is a twin-engined anti-submarine warfare (ASW) helicopter designed for shipboard use by Canadian naval forces, based on the US Navy's SH-3 Sea King. Most CH-124s were assembled in Quebec by United Aircraft of Canada. The CH-124 served with the Royal Canadian Navy (RCN) and Canadian Armed Forces from 1963 to 2018.
The AérospatialeSA 321 Super Frelon is a three-engined heavy transport helicopter produced by aerospace manufacturer Sud Aviation of France. It held the distinction of being the most powerful helicopter to be built in Europe at one point, as well as being the world's fastest helicopter.
The Sikorsky H-34 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 the Westland Wessex and by Sikorsky as the S-58T. The H-34 was also produced under license in France by Sud Aviation.
The Piasecki HUP Retriever or H-25 Army Mule, later UH-25, is a compact single radial engine, twin overlapping tandem rotor utility helicopter developed by the Piasecki Helicopter Corporation of Morton, Pennsylvania. Designed to a United States Navy specification, the helicopter was produced from 1949 to 1954, and was also used by the United States Army and foreign navies. The HUP/H-25 was the first helicopter to be produced with an autopilot and also the first to perform a loop.
The Sikorsky HH-52 Seaguard is an early amphibious helicopter designed and produced by American helicopter manufacturer Sikorsky Aircraft. It was the first of the company's amphibious rotorcraft to fly and the United States Coast Guard's first turbine-powered helicopter and first amphibious helicopter.
The Vought-Sikorsky VS-300 is an American single-engine helicopter designed by Igor Sikorsky. It had a single three-blade rotor originally powered by a 75 horsepower (56 kW) engine. The first "free" flight of the VS-300 was on 13 May 1940. The VS-300 was the first successful single lifting rotor helicopter in the United States and the first successful helicopter to use a single vertical-plane tail rotor configuration for antitorque. With floats attached, it became the first practical amphibious helicopter.
Air-sea rescue, and aeronautical and maritime search and rescue (AMSAR) by the ICAO and IMO, is the coordinated search and rescue (SAR) of the survivors of emergency water landings as well as people who have survived the loss of their seagoing vessel. ASR can involve a wide variety of resources including seaplanes, helicopters, submarines, rescue boats and ships. Specialized equipment and techniques have been developed. Both military and civilian units can perform air-sea rescue. Its principles are laid out in the International Aeronautical and Maritime Search and Rescue Manual. The International Convention on Maritime Search and Rescue is the legal framework that applies to international air-sea rescue.
Changhe Aircraft Industries Corporation (CAIC) is a Chinese helicopter manufacturer and supplier to the Chinese military. It is a member of the Aviation Industry Corporation of China (AVIC). The company is based in the city of Jingdezhen in Jiangxi province. Changhe employs 4300 employees in two production facilities with 1.29 million sq. metres and 0.22 million sq. metres of construction area. It has a joint venture with Agusta Helicopter and relationship with Sikorsky Aircraft Corporation. Its subsidiary, Changhe Machinery Factory, is a major automobile company in China.
The Sikorsky S-61R is a twin-engine helicopter used in transport or search and rescue roles. A developed version of the S-61/SH-3 Sea King, the S-61R was also built under license by Agusta as the AS-61R. The S-61R served in the United States Air Force as the CH-3C/E Sea King and the HH-3E Jolly Green Giant, and with the United States Coast Guard as the HH-3F, nicknamed "Pelican". This article covers several different variants of this type in different roles, one major difference compared to the S-61 was a rear ramp.
The Avicopter AC313 is a civilian helicopter built by Avicopter. It is a development of the earlier Harbin Z-8, itself a locally produced version of the Aerospatiale Super Frelon.