The M5 "Stuart" (also "General Stuart") was an extension of the original M3 Stuart Light Tank line of 1941 and brought about by the American military relocation of vital war-making supplies - namely the Continental aero engine used in the M3. This initiative begat a modified Stuart light tank initially known as the "M4" though later changed to "M5" to differentiate it from the classic M4 Sherman medium tank. The British Army continued naming their American tanks and the M5 was known as "Stuart VI" (the M3A3 was the "Stuart V").
As completed, the M5 now showcased a paired set of Cadillac V8 296-horsepower automobile engines which forced a reworking of the engine deck at the rear of the hull. The engines were coupled to individual Hydra-Matic transmission systems running through a 2-speed transfer case and provided improved running performance and noise reduction over the original Continental installation. A new front hull design, based on the M3A3 Stuart, was implemented and brought about improved frontal ballistics protection. The lack of a frontal vertical face on the new hull superstructure ended with the driver's hatch relocated to the hull roof. The new tank retained the same 37mm M6 main gun as the M3 which gave good service against light-armored vehicles, light fortifications and enemy infantry (the latter when using High-Explosive (HE) projectiles). Defense was through a coaxial 0.30 Browning machine gun as well as a bow-mounted machine gun at front-right. The resulting changes produced a much roomier interior in the M5 when compared to the M3 before it. Its crew numbered four - driver, commander, gunner and bow machine gunner/radio operator.
After adoption by the U.S. Army and serial production beginning through General Motors (Cadillac Division Detroit) in April of 1942, the M5 Stuart began the slow process of replacing in-service M3 Stuarts across the various American theaters. Additional manufacture came from Massey Harris, an agricultural machinery producer, and from Southern California factories by August. Production completed in December with a total initial run of 2,074 M5 vehicles.
In time, an improvement was taken on and this became the "M5A1". A larger turret was installed that was similar to the one in use with the M3A3. An optional 0.30 caliber Browning Anti-Aircraft (AA) gun was fitted to the exterior turret side though this required an exposed crewmember to operate. The existing assembly lines were then ordered to produce the new mark and American Car and Foundry was added to help bring about a total stock of 6,810 M5A1s by the middle of 1944. American Car and Foundry was also charged with modifying a stock of 775 existing M5A1s to new, late-war standards. A shielded 0.30 caliber machine gun position was eventually introduced in M5A1 production which protected the operator to a degree.
The M5 line served in a frontline role as the primary American light tank until 1944 to which it was, itself, replaced by the newer M24 "Chaffee" Light Tank. M5 Light Tanks operated primarily in the Pacific and Burmese theaters where Japanese armor was comparable and its anti-weaponry was not as potent as what was seen with the Germans in Africa and Europe. It was during the 1943 Battle of Kasserine Pass that showcased the critical tactical limitations of light tank battalions for the U.S. Army. This led to their disbanding and reforming with medium tank companies while being used primarily in the armed scouting / reconnaissance role. Medium tanks would handle enemy tanks directly.
Variants of the M5 proved plenty during the war years. Marks included a command tank form with increased communications equipment and a turret-less reconnaissance model armed solely with a 0.50 caliber heavy machine gun - brought about under the "T8" designation. Flame tanks were also developed which installed a flame gun in place of the machine gun. A turret-less M5A1 formed the basis of the "M5 Dozer" which saw a dozer blade fitted for engineering work. The 75mm Howitzer Motor Carriage M8 was an Self-Propelled Artillery (SPA) system built atop the M5 chassis and outfitted with the 75mm M2/M3 howitzer. 1,778 examples of this type were ultimately produced. Similarly, the 75mm Howitzer Motor Carriage M8A1 followed suit though atop the M5A1 chassis. The T82 was a proposed howitzer-carrying vehicle managing a 105mm weapon though this initiative was given up in 1945. Another abandoned M5A1 offshoot was the T27/T27E1 development which mated a turret-less M5A1 with an 81mm mortar. This project too was abandoned - though in April of 1944.
Post-war use of M5s included combat service by both India and Pakistan during the 1947 Independence War. Other known operators went on to include Brazil and Haiti.