The M3 Stuart/light tank M3 was a US light tank of World War II first introduced into service in the British Army in early 1941. Later, an improved version of the tank entered service as the M5 in 1942, to be supplied to British and other allied Commonwealth forces under lend-lease, prior to the entry of the United States into the war.
The British service name "Stuart" came from the U.S. Civil War Confederate general J. E. B. Stuart and was used for both the M3 and the derivative M5 light tank. Unofficially, they were also often called "Honeys" by the British, because of their smooth ride. In U.S. use, the tanks were officially known as "light tank M3" and "light tank M5".
Stuarts were first used in combat in the North African campaign; about 170 were used by the British forces in Operation Crusader (18 November – 30 December 1941). Stuarts were the first American-crewed tanks in World War II to engage the enemy in tank versus tank combat when used in the Philippines in December 1941 against the Japanese.Hunnicutt (Stuart) p. 395Zaloga (Armored Thunderbolt) p. 301 Outside the Pacific War, in later years of WWII, the M3 was used for reconnaissance and screening.
Development
Observing events in Europe and Asia during World War II, American tank designers realized that the light tank M2 was becoming obsolete and set about improving it. The upgraded design, with thicker armor, modified suspension and new gun recoil system was called "light tank M3". Production of the vehicle started in March 1941 and continued until October 1943.
By the standards of the era for light tanks, the Stuart was fairly heavily armored. It had 38 mm of armor on the upper front hull, 44 mm on the lower front hull, 51 mm on the gun mantlet, 38 mm on the turret sides, 25 mm on the hull sides, and 25 mm on the hull rear.Zaloga 1999, p. 31 Like its direct predecessor, the M2A4, the M3 was initially armed with a 37 mm M5 gun and five .30-06 Browning M1919A4 machine guns: one coaxial with the main gun, one on top of the turret in an M20 anti-aircraft mount, another in a ball mount in right bow, and two more in the right and left hull sponsons. Later, the main gun was replaced with the slightly longer M6, and the sponson machine guns were removed.
The M3 and M3A1 variants were powered by an air-cooled radial engine, either a gasoline-fueled 7-cylinder Continental W-670 (8,936 built) or a 9-cylinder Guiberson T-1020 diesel (1,496 built).Hunnicutt (Stuart) p. 127 and p. 153 Both of these powerplants were originally developed as aircraft engines. Internally, the radial engine was at the rear and the transmission at the front of the tank's hull. The driveshaft connecting the engine and transmission ran through the middle of the fighting compartment. The radial engine's crankshaft was positioned high off the hull bottom and contributed to the tank's relatively tall profile. When a revolving turret floor was introduced in the M3 hybrid and M3A1, the crew had less room. A further 3,427 M3A3 variants were built with modified hull (similar to the M5), new turret and the Continental W-670 gasoline engine.Hunnicutt (Stuart) p. 164 In contrast to the M2A4, all M3/M5 series tanks had a trailing rear idler wheel for increased ground contact, whereas on the M2 the idler wheel was off the ground and did not aid in suspension.
M5 Stuart
To relieve wartime demand for the radial aero-engines used in the M3, a new version was developed using twin Cadillac V8 automobile engines and twin Hydra-Matic transmissions operating through a transfer case. This version of the tank was quieter, cooler and roomier; the automatic transmission also simplified crew training. The new model (initially called M4 but redesignated M5 to avoid confusion with the M4 ShermanZaloga (M3/M5 Stuart) p. 17) featured a redesigned hull with a raised rear deck over the engine compartment, sloped glacis plate and driver's hatches moved to the top. Although the main criticism from units using the Stuarts was that it lacked firepower, the improved M5 series kept the same 37 mm gun. The M5 gradually replaced the M3 in production from 1942 and, after the M7 project proved unsatisfactory, was succeeded by the light tank M24 in 1944. Total M5 and M5A1 tank production was 8,884; an additional 1,778 M8 75 mm howitzer motor carriages based on the M5 chassis with an open-top turret were produced.
Production of M3 and M5 Month M3 series M5 series March 1941 1 April 1941 127 May 1941 211 June 1941 221 July 1941 253 August 1941 281 September 1941 309 October 1941 400 November 1941 338 December 1941 410 January 1942 378 February 1942 363 March 1942 418 April 1942 544 3 May 1942 619 16 June 1942 711 60 July 1942 762 127 August 1942 694 268 September 1942 620 449 October 1942 944 593 November 1942 199 605 December 1942 1,587 737 January 1943 104 401 February 1943 443 400 March 1943 475 402 April 1943 475 293 May 1943 475 260 June 1943 475 283 July 1943 475 351 August 1943 500 403 September 1943 47 198 October 1943 251 November 1943 348 December 1943 473 January 1944 490 February 1944 458 March 1944 513 April 1944 344 May 1944 134 June 1944 24 Total 13,859 8,884
Light-tank doctrine Light tanks were issued to tank battalions (one of the four companies was a light tank company), light tank battalions and cavalry reconnaissance squadrons. The original role of the light tank in these formations was similar to medium tanks and they were expected to engage enemy armor with AP rounds and enemy positions with HE rounds. As a result, tank gunnery training for light and medium tankers was common.Armored Force Field Manual FM 17-12, Tank Gunnery, 22 April 1943 p. 18-19
US Army Field Manuals written before 1944 clearly show that light tanks were to be part of an armored assault on enemy positions, and examples of fire on enemy armor were in these manuals.Armored Force Field Manual FM 17-30, Tank Platoon, 22 October 1942, p 44 When pursuing an enemy, light tank battalions were expected to move parallel with enemy columns and, together with accompanying infantry and engineer units, seize "critical terrain that will block hostile retreat".Armored Force Field Manual FM 17-33 The Armored Battalion – Light and Medium, 18 September 1942, p 112 Despite the fact that light tank platoons were not expected to function as a reconnaissance unit, they could be used for reconnaissance purposes.Armored Force Field Manual FM 17-30 Tank Platoon, 22 October 1942, p 55-56 In this role, they were expected to remain behind the main reconnaissance force as the support element and augment the firepower whenever enemy contact was made.Cavalry Field Manual FM 2-30, Cavalry Reconnaissance Squadron, Mechanized, 28 August 1944, p. 2
Combat history
War in North Africa and Europe British and other Commonwealth armies were the first to use the light tank M3, as the "Stuart", in combat.Hunnicutt (1992) p. 391 From mid-November 1941 to the end of the year, about 170 Stuarts (in a total force of over 700 tanks) took part in Operation Crusader during the North Africa Campaign, with poor results. This is despite the fact that the M3 was superior or comparable in most regards to most of the tanks used by the Axis forces. The most numerous German tank, the Panzer III Ausf G, had nearly identical armor and speed to the M3, and both tanks' guns could penetrate the other tank's front armor from beyond . The most numerous Italian tank (and second most numerous Axis tank overall), the Fiat M13/40, was much slower than the Stuart, had slightly weaker armor all around, and could not penetrate the Stuart's front hull or turret armor at 1,000 meters, whereas the Stuart's gun could penetrate any spot on the M13/40. Although the high losses suffered by Stuart-equipped units during the operation had more to do with the better tactics and training of the Afrika Korps than the apparent superiority of German armored fighting vehicles used in the North African campaign, the operation revealed that the M3 had several technical faults. Mentioned in the British complaints were the 37 mm M5 gun and poor internal layout. The two-man turret crew was a significant weakness, and some British units tried to fight with three-man turret crews. The Stuart also had a limited range, which was a severe problem in the highly mobile desert warfare as units often outpaced their supplies and were stranded when they ran out of fuel. On the positive side, crews liked its relatively high speed and mechanical reliability, especially compared to the Crusader tank,Zaloga (M3/M5 Stuart) p. 9-12Hunnicutt (Stuart) p. 391–394 which comprised a large portion of the British tank force in Africa up until 1942. The Crusader had similar armament and armor to the Stuart while being slower, less reliable, and several tons heavier. The Stuart also had the advantage of a gun that could deliver high-explosive shells; HE shells were not available for the 40 mm QF 2-pdr gun mounted by most Crusaders, severely limiting their use against emplaced anti-tank guns or infantry.Ian Hogg (1996), Tank Killing, page 138-139, Sidgwick & Jackson The main drawback of the Stuart was its low fuel capacity and range; its operational range was only cross country, roughly half that of the Crusader.
In the summer 1942, the British usually kept Stuarts out of tank-to-tank combat, using them primarily for reconnaissance. The turret was removed from some examples to save weight and improve speed and range. These became known as "Stuart Recce". Some others were converted to armored personnel carriers known as the "Stuart Kangaroo", and some were converted into command vehicles and known as "Stuart Command". M3s, M3A3s, and M5s continued in British service until the end of the war, but British units had a smaller proportion of these light tanks than U.S. units.
Eastern Front The other major Lend-Lease recipient of the M3, the Soviet Union, was less happy with the tank, considering it under-gunned, under-armored, likely to catch fire, and too sensitive to fuel quality. The M3's radial aircraft engine required high-octane fuel, which complicated Soviet logistics as most of their tanks used diesel or low-octane fuel. High fuel consumption led to a poor range characteristic, especially sensitive for use as a reconnaissance vehicle. In the letter sent to Franklin Roosevelt (18 July 1942), Stalin wrote:
Also, compared to Soviet tanks, the M3's narrower tracks resulted in a higher ground pressure, getting them more easily stuck in the Rasputitsa muddy conditions of spring and autumn and winter snow conditions on the Eastern Front. In 1943, the Red Army tried out the M5 and decided that the upgraded design was not much better than the M3. Being less desperate than in 1941, the Soviets turned down an American offer to supply the M5. M3s continued in Red Army service at least until 1944.
Italy One of the more successful uses of the M5 in combat came during the Battle of Anzio when breaking through German forces surrounding the beachhead. The tactics called for an initial breakthrough by a medium tank company to destroy the heavier defenses, followed by an infantry battalion who would attack the German troops who were being left behind the medium tanks. Since many hidden fortifications and positions would have survived the initial medium tank assault, the infantry would then be confronted by any remaining fortified German troops. Behind the infantry came the M5s of a light tank company, who would attack these positions when directed to by the infantry, usually by the use of green smoke grenades.Training memorandum number 2: lessons from the Italian Campaign , p. 47 of 162, March 1945