T20 medium tank

Medium Tank T20
The T20 with horizontal volute spring suspension
Type	Medium tank
Place of origin	United States
Specifications
Weight	29.83 t (29.36 long tons; 32.88 short tons)
Length	5.70 m (18 ft 8 in)
Width	3.00 m (9 ft 10 in)
Height	2.44 m (8 ft 0 in)
Crew	5 (Commander, gunner, loader, driver, co-driver)
Armor	62 mm
Main armament	76 mm M1 gun 70 rounds
Secondary armament	2x .30 cal Browning M1919 MG 6,000 rounds
Engine	Ford GAN V-8 470 hp (350 kW)
Power/weight	17.26/ton
Suspension	HVSS (Horizontal Volute Spring Suspension)
Operational range	160 km (99 mi)
Speed	40 km/h (25 mph)

The Medium Tank T20 was part of a series of medium tanks designed by the United States during the Second World War, to be the successor to the Medium Tank M4 "Sherman", and culminated in the M27.

Almost immediately after the M4 Sherman was standardized, the US Ordnance Department started work on a successor. The Ordnance Department had already been working on heavily armored infantry tank design for the British, using M4 parts. The new project was started on the 25 May 1942, it was originally designated M4X. Starting with the T20, the Ordnance Department initially developed three series of improved medium tank prototypes, the T20, T22, and T23. The main differences between the T20, T22 and T23 lay in the choice of transmission. The T20 used a torque converter fluid drive, the T22 a 5-speed mechanical drive similar to the M4 drive, and the T23 used an electric drive. All moved the transmission to the rear of the vehicle eliminating the need for a driveshaft running the length of the vehicle. The driveshaft used in the M3 & M4 vehicles forced the turret to be mounted higher increasing the vehicle height.

Within each different prototype series, a variety of different suspension and armament configurations were tried out, for example, the T20 had an early version of the horizontal volute spring suspension (HVSS) suspension later employed on the M4A3 Sherman, whereas the T20E3 had torsion bar suspension.

Ford GAN V8 engine with torque converter and Hydra-matic transmission 76 mm gun M1 and horizontal volute suspension r

T20E1: 75 mm automatic gun and horizontal volute suspension. This version was cancelled and the turret used on the T22E1

T20E2: 3 inch gun and torsion bar suspension. Completed as the T20E3.

T20E3: 76 mm gun and torsion bar suspension

Of the above only the T20 and T20E3 were completed, the T20E3 being converted from the T20E2 prototype. The T20 series was deemed unsuccessful on the grounds that the transmission was subject to excessive oil leaks and overheating.

Ford GAN V8 engine with M4 type mechanical transmission