An experimental family, not a production standard
The Light Tank T1 series was an American effort to replace the First World War light-tank arrangement with a more capable domestic vehicle. Beginning in 1927, it developed through several small prototype batches and rebuilds rather than settling into a mass-produced type. Cunningham manufactured vehicles within an Army Ordnance development program associated with Harry Knox. Identifying the industrial builder is not the same as attributing the entire design solely to that company. Sources
The family covers the original T1, T1E1 through T1E6, and closely connected support experiments. It is distinct from Christie's Convertible Combat Car T1: the repeated designation does not indicate the same tank. The later Light Tank T2 and the T5/M1 Combat Car and M2 development paths are related follow-ons or comparisons, not additional T1 production variants. Sources
The first T1 and the T1E1 batch
Accounts place the first development contract in 1927, when the Army was still relying heavily on its M1917 inventory. The initial vehicle used a front engine, rear fighting compartment, and a small turret arrangement. The surviving photograph of the original pilot shows a mock-up turret, which is important evidence of its development state rather than proof of a finished fighting configuration. Sources
Four T1E1 tanks and two associated cargo carriers followed. The T1E1 reduced the overhang of the original vehicle and carried its fuel externally. It was briefly standardized as Light Tank M1, but the source compilation disagrees between 14 and 24 January 1928 for that decision; both accounts place its reversal on 30 March. That short-lived designation is distinct from later vehicles called M1. Sources
The tanks went through troop and mechanical trials. A reported long-distance run exceeding 3,000 km without a serious breakdown is retained as a source-specific trial account, not evidence that every requirement had been met. Successful movement did not settle the problems of ride, crew arrangement, firepower, or future development. Sources
Improving the front-engine configuration
The T1E2 attempted to obtain more useful capability through greater power, revised armor, and an improved 37 mm weapon. Accounts associate it with a longer Browning gun but also records photographs showing the shorter M1916. These are configurations to identify, not a reason to claim that one photograph disproves every alternative gun trial. Sources
The T1E3 incorporated a different suspension arrangement, combining coil springs and hydraulic shock absorbers. It was a rebuild of a T1E1, so counting both designations as newly manufactured hulls would inflate production. The T1E5 also belonged to the effort to improve mechanical behavior, especially steering. The cited accounts do not firmly establish its exact conversion history and steering equipment. These experiments show a family changing subsystem by subsystem rather than a tidy succession of standardized production marks. Sources
The major layout change: T1E4 and T1E6
The T1E4 was a more radical departure. The engine moved to the rear, the drive was at the front, and the turret occupied a more central position. Accounts describe a Vickers-influenced layout and suspension arrangement, including leaf-sprung components. It cannot inherit every dimension, crew position, or mobility figure of the earlier front-engine machines. Sources
The T1E6 further explored the rear-engine arrangement with a substantially more powerful V12. The source specification lists 244 hp, but the apparent improvement in output cannot obscure the added mass or the need for a consistent weight basis. Later Army work moved into new development lines; the T1E4 and T1E6 are best understood as experiments that informed those decisions, not as accepted replacements delivered to operational tank units. Sources
Crew, protection, armament, and mobility
The early configuration placed the engine ahead of the crew and the turret far back. The account highlights restricted driver visibility and an unfavorable distribution of space in a two-man tank. In the T1E1, the suspension was essentially unsprung; adding speed without improving the ride could increase crew and mechanical strain. These considerations help explain why comparative evaluation did not reduce to a maximum-speed figure. Sources
The T1E1 is associated with a 37 mm M1916 gun in a T1 mounting, a coaxial.30-caliber machine gun, and source figures of 80 cannon rounds and 3,000 machine-gun rounds. Those are configuration-specific values, not defaults for every experimental member. Later weapons and mountings, including the M1924 in the rear-engine designs, remain separately recorded. The available evidence also identifies an M1918 sight for the early arrangement but does not establish one common sight installation throughout the series. Sources
Armor values vary by configuration and source. The early.25–.375-inch values and later.625-inch reports do not establish a uniform thickness on every surface. Likewise, engine output figures for the T1E1 range from 105 to 132 hp. Reported performance varied by T1 configuration. The cited T1E1 figures are 18 mph and 75 miles of range, rather than the higher speeds sometimes quoted for the wider experimental family. Sources
Production accounting and Army use
The original pilot, four T1E1 tanks, cargo carriers, later pilots, and rebuilt vehicles have to be reconciled in a hull-level ledger. A machine appearing under more than one experimental designation may represent the same chassis before and after modification. Support-carrier, mortar, and howitzer experiments also need their relationship to the tank program recorded without being counted as ordinary armed T1s. Sources
The account establishes American development and trial use, not combat service or a foreign operational fleet. Work at Fort Meade and other Army establishments concerned evaluation and mechanization rather than deployment in battle. Reliability and performance results apply to the particular vehicles and conditions tested. Sources
What the program contributed
The documented assessment treats the T1 series as a useful but unsuccessful route to a replacement light tank. It explored more than engine power: the changing vehicles tested crew placement, armor and armament growth, suspension, steering, and the suitability of a rear-engine arrangement. Sources
Its importance lies in the Army's accumulation of practical design and evaluation experience. That does not justify describing a prototype as a wartime service tank or treating each later American design as a direct T1 variant. Sources
The photographic sequence and unfinished research
Five images document the original mock-up-turret pilot and the T1E1, T1E3, T1E4, and T1E6. Their captions trace them to the 1947 Army Ground Forces Board No. 2 compilation, with separate page references. These are exterior configuration views. An open driver's hatch in the T1E6 photograph is not a complete interior view, and obscuring screens on another vehicle do not reveal hidden suspension components. Sources
Published accounts describe a T1E2 image lead that was not embedded because its download failed. That is an acquisition gap rather than an absence of photography. Sources
Photographs and image credits
Background reading and references. Each photograph has its own source and credit.
Sources and further reading
Background reading and references. Each photograph has its own source and credit.
- AFV Database, “Light Tank M1”. — Detailed T1E1 / Light Tank M1 specifications, armament, armor, automotive data, and standardization notes; cites Hunnicutt and AGF Board No. 2
- Konrad F. Schreier Jr., “U.S. Army Tank Development 1925–1940,” ARMOR, May–June 1990, official eARMOR reprint. — Official U.S. Army historical overview; useful for development sequence and interwar context
- Yuri Pasholok, translated by Peter Samsonov, “Christie’s Victim,” Armor Archives, 2015. — Detailed narrative of T1/T1E1/T1E2 development, trials, and Christie/Vickers context
- Yuri Pasholok, translated by Peter Samsonov, “Light Tanks T1E4 and T2E1: Experiments on an Ideal Platform,” Armor Archives, 2017. — Detailed T1E4/T1E6 and successor-layout context
- Timothy K. Nenninger, “The Experimental Mechanized Forces,” ARMOR, May–June 1969. — U.S. mechanized-force context and period photographs including T1E1 vehicles in mechanization logistics
- Wikimedia Commons, “File:Light Tank, T1 prototype.png”. — Public-domain U.S. Army Ordnance Department image, source AGF Board No. 2, p. 32
- Wikimedia Commons, “File:Light Tank, T1E1.png”. — Public-domain U.S. Army Ordnance Department image, source AGF Board No. 2, p. 34
- Wikimedia Commons, “File:Light Tank, T1E2.png”. — Public-domain U.S. Army Ordnance Department image, source AGF Board No. 2, p. 38; not embedded in this document because image download failed during production, but retained as photo lead
- Wikimedia Commons, “File:Light Tank, T1E3.png”. — Public-domain U.S. Army Ordnance Department image, source AGF Board No. 2, p. 42
- Wikimedia Commons, “File:Light Tank, T1E4.png”. — Public-domain U.S. Army Ordnance Department image, source AGF Board No. 2, p. 56
- Wikimedia Commons, “File:Light Tank, T1E6.png”. — Public-domain U.S. Army Ordnance Department image, source AGF Board No. 2, p. 58
- U.S. Army Center of Military History / Army Museum Enterprise, U.S. Army Ordnance Training Support Facility. — Official facility overview supporting Ordnance collection context after BRAC transfers
- Tank Encyclopedia, “Light Tank T1 Cunningham”. — Secondary overview and preservation lead.
