M561 Gama Goat

The M561 Gama Goat was a 6x6 tactical truck built for the US Army by the Consolidated Diesel Electric Company (CONDEC) in Charlotte, North Carolina, from the late 1960s into the 1970s. Its nickname combines the name of the inventor of its powered articulation joint, Roger Gamount, with 'goat' for its sure-footed, mountain-goat ability off road. About 15,000 were built.

Design

The Gama Goat is a dual-body vehicle. A front unit with the cab is joined by an articulated joint to a rear cargo unit, and the two hulls can move independently to follow very rough ground. If necessary the joint can be locked, and the vehicle can keep moving on five wheels. All six wheels are driven. Both the front and rear axles steer, with the rear wheels turning the opposite way at half the front angle, and the steering is not self-centring. Built entirely of aluminium, the truck weighs about 7,300 lb (3,310 kg) at kerb weight. It can carry a 2,900 lb payload, can be air-dropped and can swim rivers without preparation.

Power comes from a 103 hp Detroit Diesel 3-53 three-cylinder two-stroke supercharged diesel, driving through a four-speed manual gearbox and a two-range transfer case to limited-slip differentials. Top road speed is about 55 mph (89 km/h). The truck is about 5.76 m long and 2.13 m wide. Variants included an artillery tractor and an ambulance (M792).

Service

The Gama Goat performed well off road, but it suffered from mechanical problems and loud engine noise, and its unusual steering required special driver training. It was not ordered again and was eventually replaced by the M998 HMMWV.