World Military Trailer Series 55: Humvee’s predecessor on the battlefield in Vietnam, the US M561 articulated tractor

In the last issue, ""Boyang Vehicle Industry" shared with you a type of ATMAT-ISL all-terrain articulated transport vehicle mass-produced in Sweden in 1966. In this issue, we will introduce to you another type of The M561 tractor is a military vehicle that also uses an articulated structure and was used by the US military in the Vietnam battlefield! It is not an exaggeration to say that the M561 articulated tractor was specially developed for the Vietnam battlefield. The French army has proven that it has experienced World War II. After the test, the transport vehicle that performed well on the flat European continent performed poorly in the muddy terrain of Vietnam. In 1954, after the Eisenhower administration began to support South Vietnam, preparations for military operations began in the country in 1959. The Defense Research Project Agency decided to develop a heavy-duty truck that could adapt to Vietnam's terrain. Eventually, Chance Vought Corporation (later CONDEC), which had produced the F4U Corsair and A7 attack aircraft, won the bid in 1968. The "Gama Goat" 1.25-ton high-mobility cargo truck is mass-produced. As a 6×6 tractor vehicle, the design concept of the vehicle is the same as that of the ATMAT military transport vehicle. It is also composed of a tractor head and a trailer unit ( Standard military arrangement). The vehicle not only has the same strong off-road performance as the Swedish ATMAT military transport vehicle, but also can handle South Asian environments such as high humidity, water, woodlands, and mountains, and has amphibious operation capabilities. It can be transported or airdropped by C-130. The length, width and height of the M561 tractor are 5.76x2.13x2.13 meters, with a crew of 2. The body is made of aluminum alloy, the deadweight is 3300kg, the total combat weight is 4630kg, and the load capacity is 1.25/1.5. tons. It has better maneuverability and terrain adaptability than ordinary pickup trucks or 1/4ton Jeeps. The experimental version of the M561 tractor was considered to use an air-cooled engine, and the mass-produced version used a Detroit Diesel 3-53 engine. 2.6 liters, which can output 103 horsepower at 2900 rpm. In order to ensure that the engine does not get water when driving through water, the power compartment is set very high behind the cab. As a two-stroke 3-cylinder engine, it is noisy. It cannot be described as high, so the driver has to use earmuffs to protect his ears when driving the car... This is a vehicle that requires ears... The gearbox matched with the 3-53 engine can It provides 4 forward gears and 1 reverse gear. Combined with the high and low speed transfer case, it can output 8 gears, and the maximum speed can reach 88 km/h. The front and rear axles of the M561 tractor adopt coil spring shock absorbers; the intermediate vehicle. The axle uses a single leaf spring for shock absorption; the front and rear wheels are very close to the front and rear of the car, with an approach angle of 62°; the departure angle is 45°, and the concave and convex angle of the middle trailer is 140°. Wheel steering, that is, the front wheels that turn normally and the rear wheels that follow up to 50 degrees allow this "unruly goat" to achieve a turning radius of 8.8 meters. Other features of the M561 tractor include the ability to install an additional carriage behind the articulated trailer unit, as is often done with the rescue version of the vehicle. Furthermore, the M561's cab has no doors. When the vehicle is not equipped with a canvas soft top, it is quite convenient to get in and out of the vehicle; once the soft top is installed, the driver has to adjust the angle of the body to get in because the entrance and exit are small. 14,274 M561 articulated tractors were produced. The main reasons for its discontinuation were the high cost of US$8,000 (equivalent to US$60,000 today) per unit, and the inconvenience of vehicle maintenance and training caused by the complex mechanical structure. As a result, the M561 was later replaced by the HUMVESS multi-purpose medium-sized vehicle - "Hummer"! (Reference materials and pictures are from the Internet, and have been infringed and deleted)