M75 (APC)

M75
An M75 APC at the Brussels army museum.
Type	Armored personnel carrier
Place of origin	United States
Service history
In service	1952-late 1950s
Used by	United States Belgium
Wars	Korean War
Production history
Manufacturer	International Harvester Corporation
No. built	1,729
Specifications
Weight	42,000 lb (18,800 kg)
Length	204.5 inches (5.2 m)
Width	112 inches (2.85 m)
Height	108.5 inches (2.75 m)
Main armament	M2 Browning machine gun
Engine	Continental AO-895-4 6-cylinder air-cooled gasoline 295 horsepower (220 kW) (at 2,660 rpm)
Suspension	Torsion bar
Fuel capacity	150 US gallons (568 L)
Operational range	115 miles (185 km)
Speed	43 mph (69 km/h)

The M75 Armored Infantry Vehicle is an American armored personnel carrier that was produced between December 1952 and February 1954, and saw service in the Korean War. It was replaced in U.S. service by the smaller, cheaper, amphibious M59. The M75s were given as military aid to Belgium, where they were used until the early 1980s. 1,729 M75s were built before production was halted.

Towards the end of World War II, a tracked, fully enclosed armored personnel carrier was developed under the designation M44 (T16) that was based on the M18 Hellcat. The M44 was extremely large (51,000 lb combat weight); carrying 24 infantry as well as a driver, bow gunner and vehicle commander. It was evaluated at Fort Knox and Aberdeen Proving Ground after the end of the war, but, ultimately, the army rejected the M44 as being too large - at the time, their tactical doctrine required infantry squads of ten men. As a result, only a handful of M44s were built, seeing service in a number of auxiliary roles.

On 21 September 1945, a set of requirements were laid down for a squad sized armored personnel carrier, based on the chassis of the T43 cargo carrier. On 26 September 1946, the development of the T18 armored utility vehicle was approved with the International Harvester (IHC) contracted to produce four prototypes.

The original mockup, which was designed to carry 14 people, including crew, featured two remote controlled .50 caliber machine guns, which could be aimed remotely by either the commander or either of the two gunners.

The first prototype T18 dropped the assistant driver, but retained the remote controlled machine guns. The T18E1 pilot was unarmed and had a high cupola for the commander, this is sometimes referred to as pilot number 4. The T18E2 replaced the commander's cupola with a T122 machine gun mount, which could be fitted with either a .30 or .50 caliber machine gun.

Though the original T18E1 prototype was unarmed, the high cupola was replaced with a variety of machine gun mounts before the M13 cupola, with a .50 caliber machine gun, was evaluated.

The prototypes were originally powered by a six-cylinder Continental AO-895-2 air-cooled gasoline engine, which exhausted through the hull side grills. This was later replaced with the AO-895-4 in the T18E1, which exhausted through a pipe mounted horizontally across the front of the vehicle.