Gama Goat

M561 “Gama Goat”
M561 "Gama Goat"
Type	6×6 Cargo
Place of origin	United States
Service history
In service	1970s–1990s
Used by	United States, Mexico
Production history
Designer	Chance-Vought Aircraft
Designed	1962–1966
Manufacturer	CONDEC
Unit cost	$13,281
Produced	1969–1973
No. built	14,274
Variants	M792 Ambulance
Specifications
Weight	7,275 lb (3,300 kg)
Length	227 in (5.8 m)
Width	84 in (2.1 m)
Height	91 in (2.3 m)
Crew	1
Engine	Detroit Diesel 53 160 cu in (2.6 L) Diesel I3 101 hp (75 kW), 217 lbf·ft (294 N·m)
Suspension	Wheel 6×6
Operational range	420 mi (680 km)
Speed	56 mph (90 km/h)

The Gama Goat was a six-wheel drive semi-amphibious off-road vehicle originally developed for use by the US military in the Vietnam War. The 'Goat used an articulated chassis, so that from distance it appears to be a four-wheel drive vehicle pulling a two-wheel trailer, but it is a single six-wheel vehicle with a four-wheel steering arrangement with the front and rear wheels turning in opposite directions. It was famous for its ability to travel over exceptionally rough and muddy terrain.

The vehicle's nickname came from two sources; "Gama" from the name of the inventor of its powered articulated joint, Roger Gamaunt, and "Goat" for its mountain goat-like off-road ability. Its military designation was M561, 6×6 tactical 1¼-ton truck. There was also an ambulance version known as the M792. The 'Goat' is prized among military vehicle collectors because it is so unusual and in short supply. The vehicle was replaced by a variety of Commercial Utility Cargo Vehicles (CUCV) and "Humvees" (HMMWV)

The concept for the vehicle came when the French Army reported that the United States Army trucks provided to them were woefully inadequate for the terrain in Vietnam. In 1959, ARPA (now known as DARPA) funded a research project called Project "Agile" to develop a new tactical truck for the Southeast Asia theatre, as well as other projects of interest to the then-looming Vietnam War.

Several companies bid for the contract, including Clark, General Motors and LeTourneau, but on March 15, 1963, the research & development contract was awarded to Ling-Temco-Vought (LTV) aerospace, Dallas, Texas, best known for their combat aircraft (though, actually the company did have some experience in designing ground vehicles, particularly, a predecessor of Gama Goat, but they didn't have the truck assembly lines and production experience comparable to those of the mentioned car manufacturers). The principal competitor to the Goat was a tracked XM571 Articulated Utility Carrier developed by Canadair Ltd. of Montreal (yet another aerospace company,) which eventually lost the contest. The contract for the Goat was completed by LTV at cost of about $8.7 million, more than three times more expensively than when it was awarded.