T32

The successful employment of the heavily armored assault tank M4A3E2 in Europe during the Fall of 1944 emphasized the need for greater armor protection. On 7 December 1944, the Army Ground Forces recommended that the Ordnance Department develop a modification of the new Pershing tank with heavier armor, and the Army Services Forces directed that immediate action be taken to comply with this request. Two approaches were followed to solve the problem. The first produced essentially a standard Pershing with thicker armor and a lower final-drive gear ratio to maintain a reasonable level of mobility. This vehicle was designated as the heavy (later medium) tank T26E5. A longer range solution was to develop a new tank utilizing as many Pershing components as possible. On 8 February 1945, construction of four tank prototypes of such a vehicle was recommended and designated as the heavy tank T32. Formal approval for this project was recorded in March.

Technical info

T32 Technical drawings The design of the new tank proceeded on a high priority basis, and by 10 April 1945, a mock-up was almost complete and approximately 80 percent of the drawings for the first two prototypes had been released. A power package consisting of the Ford GAC V-12 engine and the cross-drive transmission similar to that planned for the heavy tank T29 was incorporated into the design. As many Pershing components as possible were utilized, but an extra road wheel was added to the torsion bar suspension, bringing the total on each side to seven. The Pershing's 23-inch wide T80E1 tracks were fitted with the five-inch extended end-connectors to further reduce the ground pressure. The high-velocity 90mm T15E2 gun with a single coaxial .30 caliber machine gun was specified for all four prototypes. This cannon used separated ammunition with a very long cartridge case, requiring a rearrangement of the interior stowage as compared to the Pershing. The 90mm T15E2 gun had a muzzle velocity of 3200 feet per second with the 24 pound AP T43 shot, and 3750 feet per second with the 16.7 pound HVAP T44 shot. The armor on the front hull was specified as five inches at 54 degrees from the vertical, and the turret varied in thickness from 11.75 inches in front to 6 inches in the rear. The front hull was cast for the first two prototypes and a .30 caliber machine gun was installed in a bow mount for the assistant driver. Both the driver and assistant driver had a single periscope fitted in the hatch cover over their seats.

Prototypes 3 and 4 were assembled using rolled armor plate on the front hull and the bow machine gun was omitted. On the latter two vehicles, the driver's wide angle periscopes were mounted in the front armor and their hatch covers were pivoted rather than hinged, allowing them to be opened without interference from the traversing turret. OCM 28680, on 9 August 1945, revised the military characteristics and recommended that prototypes 3 and 4 be designated as the heavy tank T32E1.

T32 top view Prototypes 1 and 2 were completed on 15 January and 19 April 1946, respectively, and both were shipped to Aberdeen Proving Ground. Prototypes 3 and 4 (T32E1) were completed on 14 May and 19 June 1946. Number 3 was shipped to Fort Knox and the fourth vehicle was retained at Detroit Arsenal for engineering studies. The T32 was the first tank with the cross-drive transmission to be tested at Aberdeen and Fort Knox and, as might be expected, a lot of problems were encountered. The early EX-120 version of the cross-drive had the usual teething troubles of an experimental design and required excessive maintenance to keep it going. However, it led directly to the development of the CD-850 series of cross-drive transmissions, which became the standard in American tanks.

The T29, T30, T32, and T34 series of tanks were used to evaluate numerous experimental components after World War II. Although too late for the war for which they were designed, they provided invaluable service in developing these components for later tanks. Much of the work that made the early AV-1790 engine and the CD-850 transmission a reliable power package utilized these tanks. Later, they were used in the development of other power train components, such as the XT-1400 transmission, which was tested in the T30.

click to read more...