The M2 Medium Tank was a United States Army medium tank that was first produced in 1939 by the Rock Island Arsenal, just prior to the commencement of the war in Europe. Production was 18 M2 tanks, and 94 slightly improved M2A1 tanks, for a total figure of 112. Events in Western Europe and on the Eastern Front rapidly demonstrated that the M2 was obsolete, and it was never used overseas in combat; it was used for training purposes throughout the war.
The M2's unique features included an unusually large number of machine guns, bullet deflector plates, and sloped armor on the hull front (glacis plate). The main armament was a 37 mm gun, with 32 mm armor; the M2A1 had a 51 mm gun mantlet. The features of the M2 series development, both good and bad, provided many lessons for U.S. tank designers that were later applied with great success in the M3 Lee, M4 Sherman and many other armored fighting vehicles.
| Medium Tank M2 and M2A1 | |
|---|---|
| Type | Medium tank |
| Place of origin | United States |
| Production history | |
| Manufacturer | Rock Island Arsenal |
| Number built | 18 M2s, 94 M2A1s |
| Variants | M2, M2A1 |
| Specifications | |
| Weight | 41,000 lb (18.7 metric tons) |
| Length | 5.38 m (17.7 ft) |
| Width | 2.59 m (8 ft 6 in) |
| Height | 2.82 m (9 ft 3 in) |
| Crew | 6 (Commander, driver, (4x) gunners) |
| | |
| Armor | M2 6.4–32 mm (0.25–1.3 in); M2A1 6.4–51 mm (0.25–2.0 in) |
| Main armament | 1× 37 mm Gun M3 200 rounds |
| Secondary armament | 7× (maximum 9) .30-06 Browning M1919 machine guns 12,250 rounds |
| Engine | Wright R975 EC2 air-cooled radial gasoline 400/340 hp (298/253 kW) |
| Suspension | Vertical Volute Spring Suspension (VVSS) |
| Fuel capacity | 473 liters (125 U.S. gal) |
| Operational range | 210 km (130 mi) |
| Speed | 42 km/h (26 mph) |
Rock Island Arsenal started work on a new medium tank, based on the design of the M2 Light Tank. Initially designated the T5, the redesigned model (with a 350 hp R-975 radial engine) was redesignated as the M2 Medium Tank in June, 1939. After the first 18 units had been produced at Rock Island Arsenal and evaluated by the army, the upgraded M2A1 specification was approved with a redesigned turret and a more powerful engine.
The medium tank M2 was a larger development of the M2 Light Tank. Many components were common or used a similar design, including the vertical volute spring suspension which would be used in later tanks as well. Twin-wheeled bogies were mounted externally, and rubber-bushed and rubber-shoed track proved durable on roads. The initial M2 model was powered by an aircooled Wright R-975 radial engine. For the M2A1, this engine was supercharged to provide an extra 50 hp (37 kW) for a total of 400 horsepower (300 kW), and designated as the R-975 C1 radial engine.
The M2 had a high superstructure, with a sponson-mounted machine gun in each corner. In addition, two more machine guns were fixed in the glacis plate and fired by the driver. Surmounting the superstructure was a small revolving turret armed with a 37 mm Gun M3 and a coaxial machine gun. The 37 mm gun could penetrate 46 mm of face-hardened armor sloped 30° at a range of 500 yards (457 meters), and 40 mm at 1,000 yards (914 meters). This armament configuration was a hybrid between the sponson-mounted weapons of the Mark VIII Liberty tank of World War I vintage, and the combination of turreted cannon, coaxial machine gun and glacis-mounted machine gun that was almost universal in World War II medium tanks. (Two additional .30-caliber machine guns could be mounted on pintles on either side of the turret for anti-aircraft use, bringing the total to nine—surely a record for any tank brought into service by any army.) The crew consisted of the tank commander, a driver and four gunners. The vehicle provided internal stowage for 200 rounds of 37 mm ammunition and up to 12,250 rounds of .30-caliber.
Bullet deflector plates were installed over the rear fenders. The idea behind these plates was that the tank could drive over a trench, and the rear sponson machine guns could then fire onto the plates; the bullets would deflect into the trench or the area directly behind the tank. Like the sponson machine guns themselves, the deflector plates turned out to be useless in modern warfare.
