The 20 US Army Tank Prototypes That Never Saw Action

Any preliminary models, especially of machines, have to be tested in real life. This is no different for military equipment and arms, including tanks. Though tanks were first conceived to try and end the stalemate of trench warfare in World War I, they had to be tested in battle to see if they could perform what they set out to do. Some performed extremely well, but others failed spectacularly and were rejected. (Here are history’s 15 largest tank battles, ranked.)

For example, the U.S. Army found that the Model 1917 Holt Gas-Electric tank could not handle even modest slopes because of its heavy power pack and motor. Though that knowledge led to better tank model designs that were accepted, other tank prototypes over the years were not.

To identify the prototype tanks rejected by the U.S. Army, 24/7 Wall St. reviewed a list of tanks from Military Factory, an online database of vehicles, aircraft, arms and more used by militaries across the world. The prototype tanks were ordered according to the year they were produced. Some of these tanks never even got past the development phase. All data came from Military Factory.

While many prototypes failed when tested in real-life scenarios, others were rejected simply because of poor timing, such as the end of a war when investment in further development and production was curtailed. This was the fate of the T28 Super Heavy Tank (Gun Motor Carriage T95), which was first built in 1945 — the year World War II ended. Other concepts were also too outlandish and remained in the concept stage. (Also see: The newest tanks of the modern era.)

Here are 20 tank prototypes rejected by the US military.

Model 1917 Holt Gas-Electric

• Year introduced: 1918
• Type: Prototype military vehicle
• Crew size: 6
• Number produced: 1

Skeleton Tank

• Year introduced: 1918
• Type: Prototype combat vehicle
• Crew size: 2
• Number produced: 1

War Tank America (Steam Tank)

• Year introduced: 1918
• Type: Experimental combat vehicle
• Crew size: 8
• Number produced: 1

M1919 Christie Medium Tank

• Year introduced: 1919
• Type: Prototype combat vehicle
• Crew size: 2
• Number produced: 1

M1921 (U.S. Ordnance M1921 Medium Tank

• Year introduced: 1921
• Type: Prototype medium tank
• Crew size: 2
• Number produced: 2

T1 Light Tank (Series)

• Year introduced: 1927
• Type: Prototype combat vehicle series
• Crew size: 2
• Number produced: 12

Tucker Tiger Tank (Tucker Armored Car)

• Year introduced: 1938
• Type: 4×2 wheeled armored car
• Crew size: 3
• Number produced: 1

M6 (Heavy tank M6)

• Year introduced: 1940
• Type: Heavy tank project
• Crew size: 6
• Number produced: 40

T29 (Heavy Tank T29)

• Year introduced: 1944
• Type: Heavy tank prototype vehicle
• Crew size: 6
• Number produced: 6

T14 (Assault Tank T14)

• Year introduced: 1944
• Type: Heavy tank / assault tank project
• Crew size: 5
• Number produced: 2

Medium Tank T20

• Year introduced: 1944
• Type: Prototype medium tank
• Crew size: 5
• Number produced: 4

T30 (Heavy Tank T30)

Heavy tank T30 in U.S. Army Armor & Cavalry Collection 2022 (CC BY-SA 4.0) by BlakeRichard00

• Year introduced: 1945
• Type: Heavy tank prototype
• Crew size: 6
• Number produced: 8

T28 Super Heavy Tank (Gun Motor Carriage T95)

• Year introduced: 1945
• Type: Self-propelled gun / heavy tank prototype
• Crew size: 4
• Number produced: 2

Chrysler TV-8

• Year introduced: 1954
• Type: Medium amphibious combat tank concept
• Crew size: 4
• Number produced: 0

MBT-70 (KPz-70)

• Year introduced: 1965
• Type: Main battle tank
• Crew size: 3
• Number produced: 14

AAI Rapid Deployment Force / Light Tank (RDF / LT)

Anmeldung GDELS-Mowag Kreuzlingen (CC BY-SA 4.0) by JoachimKohler-HB

• Year introduced: 1980
• Type: Light tank prototype / pilot vehicle
• Crew size: 2
• Number produced: 4