A Pershing tank of the U.S. Marine Corps during the Korean War in 1950.
||Medium tank, heavy tank
|Place of origin
||United States of America
||World War II, Korean War
||Detroit Arsenal Tank Plant
Fisher Tank Arsenal
||46 short tons (41.7 t)
||20 ft 9.5 in (6.337 m) (turret facing aft)
28 ft 4.5 in (8.649 m) (turret facing forward)
||11 ft 6 in (3.51 m)
||9 ft 1.5 in (2.78 m)
||5 (Commander, Gunner, loader, driver, co-driver)
(T26E3) Upper hull = 100mm
Hull sides = 50 to 75mm
Lower hull and turret sides= 76mm
|90 mm Gun M3
|2 × Browning .30-06
1 × Browning .50 cal.
||Ford GAF; 8-cylinder, gasoline
450–500 hp (340–370 kW)
|100 mi (160 km)
||25 mph (40 km/h) (road)
5.25 mph (8.45 km/h)(off-road)
The Pershing was the first operational heavy tank of the United States Army. It was designated a heavy tank when it was designed in WWII due to its 90mm gun, which was at the time the 2nd largest caliber gun found on an American tank, the first being the 105mm howitzer mounted on a variant of the M4 Sherman. In 1957, the U.S. developed the M103 tank, which had an even larger 120mm gun, and the M26 Pershing was re-designated as a medium tank. The tank is named after General John J. Pershing who led the American Expeditionary Force in Europe in World War I. It was briefly used both in World War II and in the Korean War.
Intended as an improvement of the M4 Sherman, the prolonged time of development meant that only a small number saw combat in the European theater, most notably in the 9th Armored Division's dramatic dash to take the Bridge at Remagen. In combat it was, unlike the M4 Sherman, fairly equal in firepower and protection to both the Tiger I and Panther tanks, but was underpowered and mechanically unreliable. This became even more evident in the Korean War, where the M26, while an overmatch for the T-34-85, had severe problems with the hilly terrain and was withdrawn in 1951 in favor of its improved derivative, the M46 Patton, which had a more powerful and reliable engine. The lineage of the M26 continued with the M47 Patton, and was reflected in the new designs of the later M48 Patton and M60 Patton.
The M26 was the culmination of a series of tank prototypes that began with the T20 in 1942 and represented a significant design departure from the previous line of U.S. Army tanks that had ended with the M4 Sherman; a number of design features were tested in the various prototypes, some of which were experimental dead-ends, but many of which would become permanent characteristics of subsequent modern U.S. Army tanks. The prototype series began as a medium tank upgrade of the M4 Sherman and ended as the U.S. Army's first operational heavy tank.
Improving on the M4
The army's first lineage of tanks had evolved from the M1 Combat Car and progressed to the M2 Light Tank, M2 Medium Tank, M3 Lee, and finally the M4 Sherman; these tanks all shared the common traits of using rear-mounted Continental air-cooled radial engines and a front sprocket drive. The rear engine-front sprocket drive layout required a driveshaft to cross underneath the turret, which increased the overall height of the tank, a characteristic shared with German tanks of World War II that also used this layout. In addition, the large diameter of the radial engines in the M4 line of tanks added further to the hull height. These mechanical features accounted for the high silhouette and large side sponsons that were characteristic of the M4 lineage.
In the spring of 1942, as the M4 Sherman was entering production, U.S. Army Ordnance began work on a follow up tank. The T20 tank reached a mock-up stage in May 1942, and was intended as an improved medium tank to follow the M4. An earlier heavy tank, the M6 had been standardized in February 1942, but proved to be a failure. The U.S. Army had no doctrinal use for a heavy tank at the time.
The T20 was designed to have a more compact hull compared to the M4. The Ford GAN V-8, a lower silhouette version of the GAA engine used in later variants of the M4, had become available. The engine had originally been an effort by Ford to produce a V-12 liquid cooled aircraft engine patterned after the Rolls-Royce Merlin, but failed to earn any aircraft orders and so was adapted as a V-8 for use in tanks; use of this lower profile engine together with the choice of a rear transmission and rear sprocket drive layout made it possible to lower the hull silhouette and eliminate the side sponsons.
The T20 was fitted with the new 76 mm M1A1 gun, developed from the 3 inch anti-aircraft gun. The 3 inch front hull armor was .5 in (13 mm) thicker than the 63 mm (2.5 in) front armor of the M4. The glacis plate slope was similar at 46°. The T20's overall weight was approximately the same as the M4.
The T20 used an early version of the horizontal volute spring suspension (HVSS), another improvement compared to the less robust vertical volute spring suspension (VVSS) of the early versions of the M4. Later prototypes of the M26 tested a torsion bar suspension, which would become the standard for future U.S. tank suspension systems.
T22 and T23
The T22 series reverted to the M4 transmission because of problems with the early Torqmatic transmission used in the T20. The T22E1 tested an autoloader for the main gun, and eliminated the loader's position with a small two-man turret.
T23 with production cast turret mounting 76mm M1A1 gun. The T23 turret would be used for the 76-mm M4 Sherman. Note the vertical volute spring suspension.
Through much of 1943, there was little perceived need within the U.S. Army for a better tank than the 75 mm M4 Sherman, and so, lacking any insights from the rest of the army as to what was needed, the Ordnance Department next took a developmental detour into electrical transmissions with the T23 series.
The electrical transmission was built by General Electric, and had the engine driving a generator that powered two traction motors. The concept was similar to the drive system of the German "Porsche Tiger" (later rebuilt as the Ferdinand/Elefant). It had performance advantages in rough or hilly terrain, where the system could better handle the rapid changes in torque requirements.
The electrical transmission T23 was championed by the Ordnance Department during this phase of development. After the initial prototypes were built in early 1943, an additional 250 T23 tanks were produced from May–December 1943. These were the first tanks in the U.S. Army with the 76 mm M1A1 gun to go into production. However, the T23 would have required that the army adopt an entirely separate line of training, repair, and maintenance, and so was rejected for combat operations.
The primary legacy of the T23 would thus be its production cast turret, which was designed from the outset to be interchangeable with the turret ring of the M4 Sherman. The T23 turret was used on all production versions of the 76 mm M4 Sherman as the original M4 75 mm turret was found to be too small to easily mount the 76 mm M1A1 gun. The first production 76 mm M4 with the T23 turret, the M4E6, was built in the summer of 1943.
T25 and T26
The T25 and T26 lines of tanks came into being in the midst of a heated internal debate within the U.S. Army in the mid-1943 to early 1944 over the need for tanks with greater firepower and armor. A 90 mm gun mounted in a massive new turret was installed in both series. The T26 series were given additional frontal hull armor, with the glacis plate increased to 4 in (10 cm). This increased the weight of the T26 series to over 40 short tons (36 t) and decreased their mobility and durability as the engine and powertrain were not improved to compensate for the weight gain.
The T26E3 was the production version of the T26E1 with a number of minor modifications made as the result of field testing. Following its introduction into combat, it was renamed the M26 in March 1945.