Design, Development, Engineering and Production

Of Armored Cars (1940-1944)

This edition, edited, annotated and illustrated by David R. Haugh

Until late 1942, there seems to have been some doubt among the using arms as to exactly what an armored car might be. As a result, in the Fall of 1942 there were under development five models of armored cars, all speedy, all well-armed, and ranging in weight from seven tons (6356kgs) to over 26 tons (23,608kgs).

To clarify this situation, and somewhat similar conditions existing in the field of the light tank, the gun motor carriage, and the scout car, and to channel the efforts of the Ordnance Department by recommending for production those models which best met the needs of the using arms, a “Special Armored Vehicle Board”, of six officers, was appointed 13 October 1942. As the recommendations of this Board had a profound effect upon the program for armored cars, a summary of its proceedings is here given.

The chief theater of war at that time was North Africa. While the experience of the Spanish Civil War had indicated the advantages of tracked and half-tracked vehicles over wheeled vehicles, the open terrain of Libya and Tunisia gave the wheeled vehicle certain advantages. For patrols and reconnaissance in desert and open country, the wheeled vehicle possessed superior mobility. The British favored armored cars, basing judgment on the success of this type of vehicle in their campaigns in Iran, Palestine, and North Africa. The Russians, operating under tactical conditions somewhat like those of the North Africa campaigns, had several models of armored cars one of which, a 6x6 car mounting a 37mm gun in a turret, resembled the armored car M1 of 1931. The German Afrika Korps was supplied with excellent vehicles of this class.

Under these influences, to the primary characteristic of speed were being added increased firepower and heavier armor. As a result, in concept and design the armored car was taking on certain aspects of the tank. This produced wide variations of characteristics within this class, and even some confusion. The Cavalry, the Armored Force, and the Tank Destroyer Command each evolved designs suited to their needs and influenced by the advice of the British, and the Ordnance Department, designed and made armored cars to fit this advice. The appointment of the Special Armored Vehicle Board followed.

This Board, called the “Palmer Board” from its president, Brig. Gen. W.B. Palmer of the Armored Force, met at Headquarters, Army Ground Forces in Washington on 14 October 1942 and the next day proceeded to Aberdeen Proving Ground to complete its mission. To expedite action, the Board submitted preliminary reports on each vehicle as considered, a final report being submitted on 5 December 1942. 

  Car, Scout, T24. Based on the chassis of the Carriage, Motor, 37-mm Gun, T14. The vehicle was requested by the Tank Destroyer Command, but no production was authorized. (Photo: US Army)

The mission of this Board was to make a comparative test of armored vehicles then under development. These vehicles, at combat weight with full stowage, were to be tested for stability, service of the piece, riding qualities (by personal test at maximum cross-country speed), obstacle crossing, fording ability, vulnerability and operation in sand, snow and mud. The vehicles considered by the Board were armored cars T13, T17, T17E1, T18, T18E1, T19, T21 and T22; the gun motor carriages T49, T55 and T57; [Gun, Motor, Carriages T49 and T57 were tracked vehicles] the scout car T24; the light tanks M3A1 and M5 and the Bigely tank.

The Board was impressed by the lack of uniformity of the equipment desired by the several using arms in identical vehicles. It recommended that when two or more using arms are equipped with identical vehicles, the equipment should be as nearly as possible identical.

In considering armored cars, the Board found some vagueness as to the definition of that type of vehicle. In the opinion of the Board, an armored car was a wheeled reconnaissance vehicle. Its general characteristics, as outlined by the Board were a weight of not over seven tons (6356kgs), combat-loaded, a weight dictated by the average bearing capacity of bridges; a top speed of over 50 miles an hour (80.5km/h); ample road clearance to negotiate rough tracks; good visibility in all directions; ability to carry a crew of four men; quickness of entrance and exit, a smooth ride, reducing the punishment of the crew at higher speeds; superior cross-country mobility for a wheeled vehicle; and a gasoline capacity for 300 miles (482.7km) of travel. The Board favored the 37mm gun as the main weapon for the armored car. It considered the ideal armored car as a vehicle simple in construction, relatively cheap and expendable, easy to transport overseas, and easy to maintain in any theater.

Several of the armored cars submitted to the Board it considered as tanks on wheels rather than reconnaissance vehicles. Their weight was from 26,000 to 53,000 pounds (11,804kgs - 24,062kgs), and by their weight, height, and width, they were not fitted for reconnaissance missions. The Board did not consider the adoption of a tank on wheels justified by any military necessity. The Board recommended that production be centered upon armored car M8 and found the other vehicles considered not suitable for further development.

The Board was directed to outline future developments to be pursued, and unanimously recommended that development be initiated of an armored car having the following characteristics:

To weigh not over 14,000 pounds (6356kgs) combat loaded, and to carry a crew of four men. To be armed with one 37mm gun, one caliber .30 machine gun mounted coaxially, and one caliber .30 machine gun mounted on the turret rear for used against aircraft or ground targets. To be armored for all-around and overhead protection similar to armored car M8 against caliber .30 armor-piercing ammunition at 50 yards (45.7m) range, with indirect vision devices for all crew positions, mantlet protection for the turret main armament, and the latest type of bullet-splash protection. To be provided with a suspension which should afford a smooth ride over moderately rough ground by independently sprung and independently articulated wheels, with a total amplitude of motion of not less than twelve inches (304.8mm) on each wheel, and to be rugged enough to withstand severe punishment. To have six wheels and eight wheels if possible, spaced at equal distances apart. To have a maximum height of 75 inches (1905mm) and a road clearance of 14 inches (355.6mm). To have a gasoline engine with a ratio of 20 horsepower per ton weight, a cruising range of 300 miles on roads, and a top speed of 55 miles an hour (88.5km/h). It was considered desirable that all electric gadgets be kept to a minimum, and that the turret be hand-operated with no gyrostabilizer and no turret basket. Hydraulic skid steering was considered desirable as an additional feature but should be separate from the service brake arrangements. The design must provide easy access, and provide room for interior ease of movement. The latest type of sighting equipment for the piece were required, and a maximum fording depth of four feet (1219mm) was desirable.

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