Hughes OH-6 Cayuse (Loach)

History of Hughes OH-6 Cayuse (loach)

The Hughes OH-6 "Cayuse" (commonly known as "The Loach") was a revolutionary light helicopter mount primarily in service with the U.S. Army and during the Vietnam War (1955-1975). Born out of the U.S.

Army's Light Observation Helicopter (LOH) program (earning it the moniker "Loach"), the model eventually proved to be an excellent helicopter system with limited service in the inventories of several U.S. allies around the world. Fewer than 2,000 prototypes of this type were produced, although the original produced a large number of usable performers, including the Hughes 500 "Defender" and the Special Forces-focused MH-6 "Bird."

After the end of World War II in 1945, the rotorcraft entered a period of further development and refinement, creating a viable helicopter solution for the military and civilian markets. The Korean War (1950-1953) was the first large-scale use of helicopters by the U.S. military in a theater, with the prospect of vertical flight as early as the 1930s.

The Korean War introduced helicopters as a search and rescue (SAR) tool and to transport the wounded in South Korea's harsh terrain.

The OH-6B was followed by a modified 420 hp Allison T63-A-720 turboshaft engine. The OH-6C is a proposed variant with a five-blade main rotor assembly linked to an Allison 25-C20 series turboshaft engine. The OH-6D is a locally licensed (Kawasaki Heavy Industries) Japanese military model based on the Hughes Model 500D series. The OH-6A was also manufactured locally in Japan, codenamed OH-6J, and a total of 387 OH-6 helicopters were produced at the Japanese factory.

The US Navy uses the OH-6 as the TH-6B for training purposes only.

The U.S. military has expanded its OH-6 product line with the EH-6B, an electronic warfare platform and command post for special forces. The MH-6B is a special forces-oriented mount with specialized equipment and optional weapons. The MH-6C is another special operations variant.

Equipped with variable weapons for light attack missions, the AH-6C is used by the 160th SOAR(A) (160th Special Operations Aviation Regiment (Airborne)), better known as the "Night Walker".

The MH-6 "Little Bird" proved to be another special operations variant, originally based on the OH-6A airframe. Introduced in 1980, these are usually equipped with missile and machine gun pods and have a crew of 2. The MH-6 was further developed through the related MD 500E platform.

After production began in 1965, the US Army's inventory continued to build up until the aircraft was officially introduced in 1966 - when the US was involved in the Vietnam War (1955-1975). Back in 1964, the U.S. Air Force took over all of the Army's fixed-wing aircraft, leaving only a fleet of helicopters to fly missions.

During the Vietnam conflict, the OH-6 Cayuse platform took on a variety of frontline operations and even CIA-directed covert missions, both unarmed and armed. Their vertical capabilities allow them to travel unimpeded over the jungle canopy and the mountainous regions of Southeast Asia, while providing all kinds of support to ground troops and the seriously wounded.

In total, 658 Cayuse helicopters were destroyed by enemy fire during the war, and another 297 were killed in accidents alone, sources said.

The Japanese OH-6 helicopter is currently (2013) being replaced by the all-new, locally designed and developed Kawasaki OH-1 series, with more than 30 produced to date. After years of development, the new helicopter entered service in 2000.

When discussing the OH-6, its record-breaking design is often forgotten - some 23 helicopter records have been set around the world, including those in speed and endurance. The OH-6 certainly rewrote the light observation category, and its outstanding design is reflected in the body still in use todaynearly 50 years after its birth.

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