America's super heavy tank - T28

As World War II was drawing to a close, all the major powers were developing monstrous super tanks of 100 tons or more in weight. The Germans had several prototypes of the Super Heavy Tank, The “Maus” (Porsche 205), weighing in at 188 tons and the Henschel E-100 at 140 tons. The British were developing the Model A39 “Tortoise”, and the Americans had their own version of the Super Tank designed to break through the Siegfried Line Defenses expected to be encountered in Germany. The proposal called for mounting a new HV 105mm T5E1/67 gun in a tank with 8" frontal armor. This gun could effectively penetrate concrete fortifications.

Work began on this Super Heavy Tank, designated as the T28, in the spring of 1945 at the Pacific Car and Foundry Co. Initial plans called for 5 prototype vehicles with an eventual total of 25 to be built. However, the war drew to a close and only 2 were ordered. These prototypes were evaluated at both the Aberdeen Proving Grounds and the Fort Knox facilities.

This tank was very heavily armored, with 12” on the front of the hull, 5-1/4” on the lower front hull and 2-1/2” on the sides. The 1 ft of frontal armor could provide protection against the famous German 88mm gun at a range of 1100 yds. The hull was cast steel and extended 2/3 of the length of the track assembly set to the rear. The suspension system and lower hull were covered with heavy skirts 4" thick. A turtle shaped superstructure had a cupola for the commander and a ring mounted caliber .50 AA machine gun. The tank had a rather low silhouette. The overall height was only 9" 51/2" at the top of the hatches.

This tank did not have the normal turret. Instead, a new 105mm (T5E1) gun was set into a ball shaped 111/2"thick mantle. This gun could achieve muzzle velocities up to 3,700 ft/sec., firing high velocity armor piercing rounds. It was a formidable weapon. The traverse was limited to 10 right and 11 left. Elevation was from -5 to +19.5 . When traveling, the gun was locked at the maximum elevation. Without a turret, this vehicle more closely resembled a Self- Propelled Gun and thus was redesignated as the T95 Gun Motor Carriage in 1945. Later, in June of 1946, the vehicle was redesignated as Super Heavy Tank T-28. The only secondary armament carried was a caliber .50 machine gun mounted above the commander’s hatch. The tank was operated by a crew of 4.

This vehicle was the largest AFV of American design in WWII. It was almost 15’ wide, 36’ long and weighed 190,000 lb. (95 tons). Because of its huge size and weight, it was equipped with 4 sets of tracks, two on each side of 19-1/2” width each. This most unusual arrangement was needed to lower the ground pressure to 11.7 lbs./sq.in. Each track assembly was made up of two complete horizontal volute suspension systems (HVSS). In order to reduce width and weight, the outermost tracks could be removed when the tank was being transported. To assist in this Herculean task, the tank carried two hydraulically assisted winchs mounted at the rear of the tank. Each track assembly weighed almost 25 tons, and two could be linked together side by side to form a unit which could be towed behind a prime mover or the tank itself! It took a crew almost 3hrs. to make this change. The running gear included a total of 64 20-1/2” wheels with rubber backed steel tracks 19-1/2” wide and rear drive with support rollers and front idler.

This monster was powered by an anemic single Ford GAF V-8 gasoline engine developing only 410 hp @ 2600 rpm. The power to weight ratio was only 5.37 hp/ton. The power train consisted of a Torquematic transmission with 3 speeds forward and 1 reverse. Brakes were an external contracting type. Steering was by controlled differential. With this power train, the tank was badly underpowered and could manage speed maximum speed of only 8 mph. Four fuel tanks held 400 gallons of gasoline, allowing a range of 100 miles. The vision and sighting equipment consisted of two periscopes type M6, one type M10E3 periscope and 1 3X telescope M8A1 type T.


There was no stabilization of the main gun. A total of 62 rounds of 105mm ammunition was carried. Manual loading was required resulting in a rate of fire of only 4 rounds per minute.

With its enormous mass, mobility was limited. Performance included: maximum grade 60 % , maximum vertical wall 24” and maximum fording depth 47”.


Two vehicles underwent intensive evaluation trials until 1947 by which time the superior heavy tanks, T29 and T32, were available. The T-29 mounted the same gun in a conventional rotating turret. The program was terminated in October of that year. At that time, this tank with its 105mm gun was the only Western tank capable of opposing the Soviet JS-3. Consideration was given to producing this tank for the contemplated invasion of Japan.

What became of these behemoths? It was reported that one tank burned up during trials, and the other was broken up for scrap during the Korean War. Yet, in 1974, a T28 was found sitting on a range at Fort Belvoir, Virginia. It is still a mystery as to where this tank spent the years 1947 to 1974. The tank was dismantled and shipped to the General Patton Museum at Fort Knox, Kentucky, where it is on prominent display.