Staff Writer (Updated: 9/28/2016):
The Chaffee was employed by American reconnaissance units in both European and the Pacific theaters during World War 2 (1939-1944). Its design stemmed from the need to equip Army forces with a light-class tank capable of mounting a 75mm main gun as the days of the 37mm tank were now long gone (the Stuarts fielded a 37m main gun). Advancements in armor design also furthered improved forms of light, medium, and heavy-class tanks the world over. Early work into a more advanced and capable light tank as handled through modifying existing M5 Stuarts but it quickly became clear that an all-new light tank chassis, hull and turret design would be need.
A pilot vehicle emerged as the T13E1 in 1943, sporting twin Cadillac 44T24 8-cylinder engines of 110 horsepower each - in much the same fashion as the preceding M5 light tank. The engines were mated to a Hydramatic transmission system which now ran through a manual transfer case ultimately netting the vehicle eight forward and two reverse speeds. The turret and gun were of all new design and construction and the vehicle sat atop a proven torsion bar suspension system for the necessary cross-country capabilities. As with the M5, the M24 gave both the driver and assistant driver steering and drive controls. The running gear included five double-tired road wheels to a hull side with three track return rollers used. The drive sprocket was at front with the track idler at rear. The engine also resided in a rear compartment, forcing the gun turret at midships and the driver at front-left. The assistant driver at front-right in the hull also managed a ball-mounted 0.30 caliber machine gun.
The vehicle evolved into the more finalized T24 pilot and was rushed through trials due to the war requirement. Production was from the General Motors Cadillac plant beginning in April of 1944 and later joined by Massey Harris in May. It was formally adopted by the U.S. Army as the Light Tank, M24 and the British named it "Chaffee" after American Army tank pioneer General Adna R. Chaffee, Jr. Operational units appeared later that year. In all, production netted 4,731 M24 vehicles from April 1944 to August 1945.
The M24 Chafee featured a suspension system not unlike the U.S. Army's M18 tank destroyer. Beyond the same Cadillac engines of the M5 Stuart series, the M24 Chaffee was an all-new offering. Its crew numbered five to include the two drivers, vehicle commander, gunner and loader. A coaxial 0.30 caliber machine gun was set next to the 75mm M6 L/40 main gun in the turret and this joined the 0.30 caliber machine gun at the bow. A 0.50 caliber M2 Browning heavy machine gun could be fitted over the rear right side of the turret and operated externally for local air and vehicle defense. A 51mm smoke grenade-launching mortar was used to provide screening against enemy eyes. On the whole, the M24 Chaffee combined firepower, speed, and agility in a complete battlefield package. Its limitation was in armor protection - purposely kept light to keep the tank mobile ahead of the main fighting force.
The M24 eventually proved reliable, fast, and maneuverable - key qualities of any combat tank. It was one of the first Allied tanks to cross the Rhine River into Germany. It was later fielded during the Korean War where it saw extensive service. Exported to many nations, it also participated with the French in the First Indochina War and other operators enacted engine upgrades and general modernization to keep the tank viable into the 1970s. The South Vietnamese Army were issued the type and stocks then fell to the conquering North Vietnamese. Operators eventually ranged from Austria and Belgium to Uruguay and Vietnam with several becoming static showpieces attached to museums or military bases.
The chassis of the M24 served as the basis for the M19 Gun Motor Carriage mounting 2 x 40mm cannons in the self-propelled anti-aircraft role. It was also the foundation for the M37 Howitzer Motor Carriage which fielded a 105mm howitzer weapon. The M41 Howitzer Motor Carriage did one better with its 155mm gun system. The T9 and T13 models were utility vehicles while the T22E1, T23E1, and T33 vehicles were cargo carriers. Cargo tractors were formed with the T42 and T43 models. The T9 saw a dozer blade installed and the T6E1 existed as a tank recovery vehicle. The T6E1 was an armored car prototype retaining the tracked nature of the M24 while fitting the turret of the M38 Wolfhound.
The M24 was also known in U.S. Army nomenclature as the "G-200".