Staff Writer (Updated: 3/21/2016):
The T28 Super Heavy Tank was built in two pilot vehicle forms by Pacific Car and Foundry, featured 12 inch thick armor and a 105mm main gun set within a fixed hull structure - essentially a heavily armored self-propelled gun designed to break through the last remnants of the German defenses, opening up gaps for other forces to exploit. The T30 was of 75 tons, protected over in 280mm of armor and fitting a 155mm main gun in a traversing turret. Designed along the same lines as the T30 was the "T29", a 70-ton product with up to 279mm of armor protection and fielding a high-velocity 105mm main gun in a traversing turret. The T29 and T30 tanks were both designed and developed at the same time and based on the T26 Pershing chassis.
American engineers took the T26E3 as a starting point, lengthening the hull and adding extra road wheels to compensate for the expected weight gains. To power the type, a Ford brand GAC series gasoline engine was selected and fitted in a rear compartment. The main differentiating feature between the T29 and T30 heavy tanks was in the former's use of a 105mm main gun instead of the latter's 155mm T7 series. Work on the T29 began in March of 1944.
Design of the T29 was rather straightforward and conventional as tanks go. The turret was set upon a tracked chassis at the middle of the design. The tracks - to each hull side - sported eight double-tired road wheels with the drive sprocket at the rear and the track idler at the front. The upper portion of the track was guided by no fewer than seven track return rollers. The hull was headed by a sloped glacis plate fitting a ball-mounted machine gun position at front-right with the driver's position at front-left. As a departure from previous wartime US tank designs, the T29 did not feature a high profile superstructure atop the hull roof. Instead, the hull roof was integrated into the design as a low-profile structure to provide enough internal working space for the engine, transmission and crew. The most characteristic feature of the T29 was its large, elongated and blocky turret managing the protruding main gun. As expected, armor was excessively thick along all major facings, measuring between 70mm (lower front hull) to 279mm (gun mantlet). The vehicle was crewed by six personnel made up of the driver, tank commander, dedicated gunner, machine gunner and two loaders - the machine gunner and driver seated in the forward hull with the rest of the crew in the turret. Overall measurements included a running length of 37 feet, 11.5 inches, a 12 feet, 5.5 inch width and a 10 feet, 6 inch height. Overall weight was approximately 70 tons.