History
Background
In January 1941, a company named Trackless Tank Corporation developed an eight-wheeled vehicle as a commercial venture. It was also known as the “Trackless Tank,” featuring no turret and only a machine gun mounted on a pintle. This prototype was tested at Aberdeen Proving Ground. While deemed unsatisfactory overall, its performance, innovative eight-wheel pneumatic strut, and independent suspension design were enough to generate interest from US Army officials. Further testing at Fort Knox suggested it could be viable as a reconnaissance armored car.
Procurement of T13 Armored Car
Following tests of the Trackless Tank prototype, the US Army issued a contract for the Trackless Tank Corporation to produce 17 test vehicles using an armored chassis. These vehicles featured independently sprung wheels, with drive provided to the three rear axles and steering handled by the two front wheels, as well as an auxiliary differential steering system. All eight wheels had individual suspension supported by pneumatic shock struts. These were driven by a Guiberson T-1020 diesel engine.
Thirteen of the vehicles were to be fitted with a light tank turret mounting a 37 mm gun and were designated as the Armored Car T13. The remaining four were intended to serve as the 3-inch Gun Motor Carriage T7. Additionally, in December 1941, the US Army requested two 105 mm Howitzer Motor Carriages T39, also based on the T13 chassis.
After the attack on Pearl Harbor, the Ordnance Committee even recommended placing contracts for 1,000 chassis before standardization. This high demand led Trackless Tank Corporation to subcontract Reo Motors Incorporated to manufacture additional T13 chassis. Two modified T13 pilot models were approved in April 1942, featuring a lengthened chassis, 12x20 combat tires, and a Continental W670-9A gasoline engine in place of the original diesel engine. However, production of 500 out of the 1,000 authorized T13s was suspended due to overlapping development of the Armored Car T20, also assigned to Reo Motors. The T20 program never advanced beyond the mock-up stage and terminated in August 1942.
Development and Testing of T13 Armored Car
After delays, the first pilot T13 was demonstrated at the subcontractor’s plant in May 1942. On June 7, 1942, two modified T13s, one with a manual and one with an air-shift transmission, were shipped to Fort Knox for testing. However, the use of many experimental components led to frequent mechanical failures. On June 29, 1942, the Armored Force Board recommended sending both pilot models back to the Trackless Tank Corporation for reworking. Consequently, the US Army instructed the subcontractor to temporarily halt production of additional pilot vehicles.
One pilot T13 was modified by the manufacturer to correct known defects. By December 1942, improvements addressed earlier design flaws, and the T13’s cross-country performance was deemed outstanding. However, the Special Armored Vehicle Board ultimately decided to terminate the T13 program. The reasons cited were that its weight had nearly doubled, making it too heavy for a reconnaissance vehicle; the steering and chain drive systems were flawed; and the pneumatic and hydraulic systems were prone to mechanical failure. On January 21, 1943, all programs involving the T13 Armored Car and its derivatives, the 3-inch GMC T7 and 105 mm HMC T39, were officially canceled. In the end, only three T13 pilot vehicles were delivered to the US Army for testing.
