Super Heavy Tank T28: American

105mm Gun Motor Carriage T-95 (T-28) during trials.

The T28 super-heavy tank was an American super-heavy tank/assault gun designed for the United States Army during World War II. It was originally designed to break through German defenses of the Siegfried Line and was later considered as a possible participant in the planned invasion of the Japanese mainland.

The near 100-ton vehicle was initially designated a heavy tank. It was re-designated as the 105 mm Gun Motor Carriage T95 in 1945, and then renamed in 1946 as the Super Heavy Tank T28.

Only two prototypes were built before the project was terminated.

Name

Initially named Heavy Tank T28 when construction was authorized in 1944, the design did not fit in the usual categories of vehicles, leading to reclassification. As it did not have its armament in a revolving turret, the Ordnance Department requested a name change to 105 mm Gun Motor Carriage T95, the change becoming official in March 1945. However, due to its heavy armor and armament—while self-propelled guns in United States service were lightly armored—it was renamed Super Heavy Tank T28 in June 1946 by OCM 37058.

Development

The T28/T95 was designed to be used for attacking the heavy defenses expected of the Siegfried Line along the western borders of Germany. The 105 mm T5E1 gun selected was known to have very good performance against concrete and "expected to be extremely effective at reducing heavy fortifications". By the time the vehicle passed trials, the German Siegfried Line had already been infiltrated and overwhelmed by the Allied forces. As a result, the T28 never left the United States, with the vehicle instead serving as an engineering study and load test vehicle at Aberdeen Proving Ground.

The need for an assault tank was first identified in 1943, with the Ordnance Department proposing that 25 vehicles could be ready for operations. A conference in March 1944 between the Ordnance Department and Army Ground Forces resulted in agreement to build five. The Pacific Car and Foundry Company were supplied with the design in March 1945, completed final design and had the first hull welded by August. By the time the first tank was completed and ready for combat, the war was over. The plan for five was reduced to two.

As it did not have a turret, but a fixed casemate mount instead for its main armament (as German Jagdpanzers and Soviet Samokhodnaya Ustanovka-designation combat vehicles did), and the 105 mm gun fitted could only elevate from 19.5° to −5° and traverse from 10° right to 11° left of the center line, the T28 more closely resembled an assault gun, and was redesignated as "T95 gun motor carriage" in 1945, but in June 1946, the vehicle was redesignated again as "super heavy tank T28".

Two prototypes of the T28 were built. They underwent evaluation at the Aberdeen Proving Ground and Fort Knox facilities until 1947. In 1947, one of the T28s was heavily damaged by an engine fire during trials at Yuma Proving Ground and was broken up and sold for scrap. The T28 never went into service due to the obsolete design, high maintenance costs, and the heavy weight, which made transportation overseas difficult, but was retained to test the "durability of components on such a heavy vehicle". Work on it ended before completion as the War Department decided to stop the development of vehicles of that sort of weight and the T28 program terminated in October 1947. By that point, the T29 and T30 turreted heavy tank designs had been built. The T29 mounted the same gun as the T28 in a conventional rotating turret. The T30 was developed with a larger-caliber gun and more powerful engine. The T29 program was used to test mechanical components for future tank designs.

Design

The original plan was to build five prototype vehicles, with a production total of 25. Its total weight when fully equipped would have reached 95 tons (86 tonnes). To lower ground pressure, instead of two tracks, it used four tracks that projected forward of the hull, each 20 inches (495 mm) wide. The outer tracks could be detached within two hours for rail transport: After removal, they could be fixed together to make a unit that could be towed behind the tank. Due to its extreme weight and low engine power, the T28 had extremely limited obstacle-crossing ability and could not cross any of the portable bridges available at the time, and so was considered impractical in the field and not suitable for production.

The T28 had no conventional turret, with a casemate style hull instead, giving it a comparatively low profile, as the later examples of the fully enclosed Jagdpanzer-family of German tank destroyers, not entirely dissimilar to the 50 short-ton weight German Jagdpanther. Its main armament was a 105 mm T5E1 gun in a ball-shaped gun mantlet set into the vertical hull front. The traverse was limited to 10° right and 11° left, and elevation from 19.5° to −5°. When traveling, the gun was locked at the maximum elevation. The only other armament was a .50 cal. (12.7 mm) M2 Browning machine gun on a ring mount above the commander's hatch for anti-aircraft use. The main gun—65 calibers long—had a muzzle velocity of 3,700 feet per second (1,130 m/s), with a range of up to 12 miles (19 km).

The armor was very thick compared to other tanks of the time, up to 12 inches (305 mm) thick on the front. This was considered heavy enough to provide protection from the German 88 mm gun used as tank and anti-tank guns. The lower hull front had 5.25 in (130 mm) of armor, and the sides 2.5 in (64 mm). The suspension system and lower hull were covered with 4-in (100 mm) thick steel skirts. The engine was a gasoline-powered Ford GAF V-8, delivering 500 hp, at 2600 rpm through the Torqmatic transmission; which left the vehicle underpowered, geared down to a top speed of about 8 mph (13 km/h) and greatly limited its obstacle-climbing capability. Although the vehicle was originally to feature the electric transmission of the Medium Tank T23, this was later changed to the mechanical transmission of the Medium Tank T26 due to the unreliability of the system.

General Information

Type: Super-heavy tank, assault gun

Place of origin: United States

Used by: United States

Manufacturer: Pacific Car and Foundry

Produced: 1945

Number built: 2

Surviving Vehicle

In 1974, the last prototype was discovered abandoned in a field at Fort Belvoir, Virginia. Camouflaged in the middle of some bushes, it is unknown where it spent the intervening 27 years. It is the sole remaining example of these tanks and was exhibited at the Patton Museum of Cavalry and Armor in Kentucky. In 2011, it was shipped to its new home at U.S. Army Armor & Cavalry Collection, Fort Benning, Georgia. It was placed in the new Patton Park, which is a plot of 30 acres where nine of the tanks being stored at Fort Benning are now displayed. The vehicle was damaged in January 2017 during transit to another facility for external refurbishment when it broke loose from the M1070 HET carrying it. The transporter failed to negotiate a downhill slope and subsequent turn at a safe speed, causing the securing chains to break and allowing the T28 to slide off the trailer. Despite then rolling into a ditch, only minor repairable damage was sustained to two bogies. The outer track units had been removed.

Specifications

Mass: 95 short tons (85 long tons; 86 t)

Length: 36 ft 6 in (11.1 m)

Width: 14 ft 10 in (4.52 m)

Height: 9 ft 4 in (2.84 m)

Crew: 4

Armor: 12 in (305 mm)

Main armament: 105 mm T5E1 gun, with 62 rounds

Secondary armament: .50 cal (12.7 mm) Browning heavy machine gun, with 660 rounds

Engine: Ford GAF V-8 gasoline, 500 hp (372 kW)

Power/weight: 5.8 hp/tonne

Suspension: double tracks, horizontal volute spring

Operational range: 100 miles (160 km)

Maximum speed: 8 mph (13 km/h)

Bibliography

Hunnicutt, Richard Pearce (1988). Firepower: A History of the American Heavy Tank. Novato, California: Presidio Press.

 

105mm Gun Motor Carriage T-95 (T-28) during trials. 

105mm Gun Motor Carriage T-95 (T-28) during trials. 

105mm Gun Motor Carriage T-95 (T-28) during trials. 

Front view of 105mm Gun Motor Carriage T-95 (T-28) during trials. 

Rear view of 105mm Gun Motor Carriage T-95 (T-28) during trials. 

105mm Gun Motor Carriage T-95 (T-28) at  Pacific Car and Foundry Company.

105mm Gun Motor Carriage T-95 (T-28) during trials compared with the M22 Locust light tank. When traveling, the gun was locked at the maximum elevation. It also had a .50 inch (12.7 mm) M2 Browning machine gun mounted above the commander's hatch. The main gun had a muzzle velocity of 3,700 feet per second (1,130 m/s), with a range of up to 12 miles (19 km). The armor was very thick compared to other tanks of the time, up to 12 inches (300 mm) thick on the front. This was considered heavy enough to provide protection from the German 88mm gun used as tank gun and anti-tank guns. The lower hull front had 5.25 in (130 mm) of armor, and the sides 2.5 in (64 mm). The suspension system and lower hull were covered with 4-in (100 mm) thick steel skirts. The engine was a gasoline-powered Ford GAF V-8, delivering 500 hp, which left the vehicle underpowered with a top speed of about 8 mph (13 km/h) and greatly limited its obstacle-climbing capability.

105mm Gun Motor Carriage T-95 (T-28) during trials.

105mm Gun Motor Carriage T-95 (T-28) during trials.

T28 during firing trials at Yuma Proving Ground in 1947. The vehicle was damaged by an engine fire during these trials.

105mm Gun Motor Carriage T-95 (T-28) at Aberdeen Proving Ground, October 3, 1946.

105mm Gun Motor Carriage T-95 (T-28) during trials.

105mm Gun Motor Carriage T-95 (T-28) during trials.

105mm Gun Motor Carriage T-95 (T-28) during trials.

T-28 roof details.

105mm Gun Motor Carriage T-95 (T-28) and the pair of outer tracks being readied for towing.

105mm Gun Motor Carriage T-95 (T-28) outer tracks.

Interior view of T-28.

Interior of Commander's Station in the T-28.

The T28 Super Heavy Tank climbing on a M15 trailer of the M25 "Dragon Wagon" tank transporter in Aberdeen, October 1946.

The T28 Super Heavy Tank during transport on the M25 "Dragon Wagon" tank transporter.

105mm Gun Motor Carriage T-95 (T-28).

GMC T95 exterior stowage front view.

Interior arrangement of the 105mm Gun Motor Carriage T-95 (T-28).

105mm Gun Motor Carriage T-95 (T-28) without the outer tracks.

105mm Gun Motor Carriage T-95 (T-28) towing the pair of outer tracks.

105mm Gun Motor Carriage T-95 (T-28) without the outer tracks.

105mm Gun Motor Carriage T-95 (T-28) without the outer tracks.

105mm Gun Motor Carriage T-95 (T-28) without the outer tracks.

105mm Gun Motor Carriage T-95 (T-28) at the beginning of the removal of the outer track.

105mm Gun Motor Carriage T-95 (T-28) during removal of the outer track.

105mm Gun Motor Carriage T-95 (T-28) after removal of outer track.

105mm Gun Motor Carriage T-95 (T-28)  outer track after removal.

105mm Gun Motor Carriage T-95 (T-28), left,  towing the outer tracks, right.

105mm Gun Motor Carriage T-95 (T-28), left,  towing the outer tracks, right.

Position of towing cables when towing outer tracks for T95.

The T28 is used in test loading a T79 100-ton Semitrailer in April 1948.

The detached outboard track units of T95 No.1 as they were transported by rail to the Aberdeen Proving Ground on 16 January 1946.

A view of the T28 with its outboard tracks fitted inside LST-1153.

The T28 leaving the LST-1153 ramp and driving onto a causeway.

On 3 May 1948, the T28 unloading from the LCT(6) at Lynnhaven Roads, Virginia (Virginia Beach, east of Norfolk).

This is how the T28 was found. In 1974, the last prototype was discovered abandoned in a field at Fort Belvoir, Virginia. Camouflaged in the middle of some bushes, it is unknown where it spent the intervening 27 years. It is the sole remaining example of these tanks and was exhibited at the Patton Museum of Cavalry and Armor in Kentucky. In 2011, it was shipped to its new home at Fort Benning, Georgia. It was placed in the new Patton Park, which is a plot of 30 acres where nine of the tanks being stored at Fort Benning are now displayed. The vehicle was damaged in January 2017 during transit to another facility for external refurbishment when it broke loose from the M1070 HET carrying it. The transporter failed to negotiate a downhill slope and subsequent turn at a safe speed, causing the securing chains to break and allowing the T28 to slide off the trailer. Despite then rolling into a ditch, only minor repairable damage was sustained to two bogies. The outer track units had been removed.

The civilian is probably the individual who discovered the T-28, being thanked for finding the vehicle.

Close-up of T28 Super Heavy Tank showing the front view of the double tracks.

Close-up of T28 Super Heavy Tank showing the rear view of the double tracks.

This winch was used to remove/install the outer set of tracks.

105mm Gun Motor Carriage T-95 (T-28) with towing arrangement for the outer tracks.

 

1943 early conceptual artwork for what would become the T28. At this point, it was known simply as the A.T. Project.

In this piece of concept art, we can see the design has matured considerably and is starting to look more like the end design. Note the M26 Pershing-style gun mantlet.

The outer tracks, removed and paired together for transport.

The completed wooden T95 mock-up in May 1945.

T95 No.2 half way through having its outboard tracks removed in March 1946.

T95 towing the outboard track units on 21 March 1946.

T95 No.2 at Fort Knox during demonstrations in April/May 1946.

A frontal view of T95 No.2 traversing some rough terrain during a demonstration at Fort Knox in April/May 1946. Note the complex shape of the frontal armor.

The T28 being loaded onto the LCT(6) at Aberdeen. A guide wire was used to keep the trailer straight as the vehicle was reversed into position.

The chained down T28 aboard the LCT(6) while in transit. Note the foul weather windscreen mounted on front of the driver’s cupola.

T28 Super Heavy Tank at the US Army Armor & Cavalry Collection. (Schierbecker, 30 April 2023)