T20 Medium Tank

Last updated
Medium Tank T20
T20 tank pilot at Fisher plant.png
The T20 with horizontal volute spring suspension
Type Medium tank
Production history
No. builtT20 - 2 pilot
T22- two pilot
T23 - 248 [1]
Specifications
Mass29.83 t (29.36 long tons; 32.88 short tons)
Length5.70 m (18 ft 8 in)
Width3.00 m (9 ft 10 in)
Height2.44 m (8 ft 0 in)
Crew5 (Commander, gunner, loader, driver, co-driver)

Armor 62 mm
Main
armament
76 mm gun M1A1
70 rounds
Secondary
armament
2x .30 cal Browning M1919 machine guns
6,000 rounds
EngineGAN V-8 petrol
Power/weight17.26/ton
SuspensionHVSS (Horizontal Volute Spring Suspension)
Operational
range
160 km (99 mi)
Maximum speed 40 km/h (25 mph)

The Medium Tank T20, Medium Tank T22 and Medium Tank T23 were prototype medium tanks, developed by the United States Army during World War II. They were designed as successors to the M4 Sherman. The standard main weapon for production versions of these designs was to be the 76 mm M1.

Contents

In July 1943, on the basis that the 75 mm-armed M4 was becoming obsolete, the US Army Ordnance Department requested that the 76 mm-gunned T23E3 and T20E3 go into production the M27 and M27B1. However, the request was rejected and neither design was ever mass-produced. The Army did not consider it necessary to interrupt M4 production for a vehicle for which they did not perceive a requirement and the introduction of the 76 mm gun to the tank force was opposed by the Armored Ground Force.

Successive evolution of the basic design culminated in the M26 Pershing.

Design and development

Almost immediately after the M4 Sherman was standardized, the US Ordnance Department started work on a successor. The Ordnance Department had already been working on a heavily armored infantry tank design for the British, using M4 parts. [2] The new project was started on the 25 May 1942, it was originally designated M4X. [3] The specification was 32 short tons, "automatic" 75mm gun, 4 in (100 mm) of armor and a top speed of 25 mph (40 km/h). [4]

After a wooden mockup produced by Fisher, Ordnance (in agreement with Armored Force Board) set out three pilot models to be built with different combinations of armament but interchangeable turrets. All would use the Ford GAN V-8 engine driving Hydra-matic transmission through a torque converter. The T20 would have the 76mm gun, the T20E1 the automatic 75mm and the T20E2 a 3-inch gun. T20 and T20E1 would be fitted with horizontal volute spring suspension (HVSS) but the T20E2 would have had torsion bar suspension. [4]

Starting with the T20, the Ordnance Department initially developed three series of improved medium tank prototypes, the T20, T22, and T23. The main differences between the T20, T22 and T23 lay in the choice of transmission. [4] The T20 used a torque converter fluid drive, the T22 a 5-speed mechanical drive similar to the M4 drive, and the T23 used an electric drive. All moved the transmission to the rear of the vehicle eliminating the need for a driveshaft running the length of the vehicle. The driveshaft used in the M3 and M4 vehicles forced the turret to be mounted higher increasing the vehicle height.

T20 series

T20E3, which replaced the T20's HVSS with torsion bar suspension T20E3.jpg
T20E3, which replaced the T20's HVSS with torsion bar suspension

All the T20 models used the Ford GAN V8 engine with Torqmatic torque converter transmission with rear drive sprocket. The hull was all-welded construction and the turrets cast. [4]

T20
76 mm gun M1 and horizontal volute spring suspension. Built by Fisher and completed in June 1943. [4]
T20E1
Planned to be 75 mm automatic gun and horizontal volute spring suspension but cancelled and turret used on the T22E1. [4]
T20E2
Intended to have 3 inch gun and torsion bar suspension but completed by Fisher with 76mm gun and designated T20E3. [3]
T20E3
76 mm gun and torsion bar suspension [4]

The T20 and T20E3 were tested but the transmission leaked and overheated. Any further work on them was stopped at end of 1944. [4]

T22 series

Work on T22 started in October 1942 when Chrysler were contracted to build pilot tanks that were identical to the T20 including the Ford GAN V8 except for using the M4 Sherman transmission though rear wheel drive rather than positioned in the front of the Sherman's. [5] Both vehicles were built by June 1943 but as with the T20 there were transmission issues and work on the T22 was cancelled in December 1944. [5]

T22
76 mm gun and horizontal volute spring suspension
T22E1
First T22 pilot refitted with the turret built by United Shoe Machinery Corporation for the cancelled T20E1. [5] 75 mm automatic gun and horizontal volute spring suspension [6] The gun was a 75mm M3 on mount M34 which was fed by a hydraulic loader from two magazines – one with AP shells and the other with HE. [5]
T22E3
Equivalent of the T20 with 3-inch gun; cancelled during design stage. [5]

There was only one T22 constructed. The T22E1 was the T22 pilot vehicle re-equipped with the turret originally built for the T20E1. The 75 mm automatic gun was tested in this installation and gave a maximum rate of fire of 20 rounds a minute, but was abandoned in December 1944 on the basis that it was unreliable and larger calibre guns were now the priority.

T23 series

Production T23 T23 Prototype Electrical Transmission.jpg
Production T23

The T23 design was to be similar to the T22 but using an General Electric supplied electric transmission with M4 tracks and VVS suspension. As with T20 and T22, three pilot models were ordered from Detroit Arsenal with different armament T23 with 76mm, T23E1 with automatic 75mm and T23E2 with 3-inch gun. [7] The 75mm and 3-inch designs were cancelled before completion but the first T23 was completed and entered trials before the T20 or T22 designs; the second was ready by March 1943. [7] The T23 was found to be highly maneuverable.

T23
76 mm gun and vertical volute suspension [6] Electric transmission.
T23E1
automatic 75mm. Cancelled.
T23E2
3-inch gun. Cancelled
T23E3
76 mm gun and torsion bar suspension

The design was classified "limited procurement" in May 1943 and 250 T23s were ordered; these were built between November 1943 and December 1944 [7] although the design was never standardized or issued to front line units. Production models featured the T80 gun mount and M1A1 76mm gun. The turret would later be used in modified form for 76mm M4 variants. The T23 was not adopted for service partly because of its untried transmission system and partly because the design had poor weight distribution and excessive ground pressure. In an attempt to rectify this, two further variants were ordered, the T23E3 with torsion bar suspension and the T23E4 with horizontal volute suspension. The T23E4 was cancelled before the design was completed, but the T23E3 prototype was completed and the torsion bar suspension was found to have reduced the ground pressure by 20% compared to the T23.

T21 Light Tank

In a related development the T21 was proposed as a replacement for the M3 and M5 series light tanks. It was to have been based on the hull and turret design of the T20 but with a maximum armor thickness of 30 mm (1.2 in) it would weigh only 24 short tons (22 t) been armed with the 76 mm gun, used either a torsion bar or use the vertical volute spring suspension of the M7 Medium Tank (originally known as T7 Light Tank). [8]

The design was prepared, but the two planned pilots were built; Armored Force wanted light tanks to weigh no more than 20 short tons (18 t). Ultimately, the T21 concept was superseded by the T24 program, which was standardized as the M24 Chaffee. [8]

Further development

With standardization of the M27 rejected, the Ordnance Department continued designing improved tanks, this time armed with 90 mm guns. The immediate result of this line of development was the T25 series – essentially a slightly larger version of the T23 – and then the bigger, better protected T26. The T26 further evolved into the T26E3, and was ultimately standardized as the M26 Pershing and accepted into service in 1944.

See also

Related Research Articles

<span class="mw-page-title-main">M4 Sherman</span> American medium tank widely used during World War 2

The M4 Sherman, officially Medium Tank, M4, was the most widely used medium tank by the United States and Western Allies in World War II. The M4 Sherman proved to be reliable, relatively cheap to produce, and available in great numbers. It was also the basis of several other armored fighting vehicles including self-propelled artillery, tank destroyers, and armored recovery vehicles. Tens of thousands were distributed through the Lend-Lease program to the British Commonwealth and Soviet Union. The tank was named by the British after the American Civil War General William Tecumseh Sherman.

<span class="mw-page-title-main">M26 Pershing</span> American medium/heavy battle tank (1944–1951)

The M26 Pershing is a heavy tank/medium tank formerly used by the United States Army. It was used in the last months of World War II during the Invasion of Germany and extensively during the Korean War. The tank was named after General of the Armies John J. Pershing, who led the American Expeditionary Force in Europe in World War I.

<span class="mw-page-title-main">M24 Chaffee</span> American light tank

The M24 Chaffee was an American light tank used during the later part of World War II; it was also used in post–World War II conflicts including the Korean War, and by the French in the War in Algeria and the First Indochina War. In British service it was given the service name Chaffee after the United States Army General Adna R. Chaffee Jr., who helped develop the use of tanks in the United States armed forces. Although the M41 Walker Bulldog was developed as a replacement, M24s were not mostly removed from U.S. and NATO armies until the 1960s and remained in service with some Third World countries.

<span class="mw-page-title-main">M3 Lee</span> American medium tank of World War II

The M3 Lee, officially Medium Tank, M3, was an American medium tank used during World War II. The turret was produced in two forms, one for US needs and one modified to British requirements to place the radio next to the commander. In British Commonwealth service, the tank was called by two names: tanks employing US-pattern turrets were called "Lee", named after Confederate general Robert E. Lee, while those with British-pattern turrets were known as "Grant", named after Union general Ulysses S. Grant.

<span class="mw-page-title-main">M18 Hellcat</span> American tank destroyer

The M18 Hellcat is a tank destroyer used by the United States Army in World War II and the Korean War. Despite being equipped with the same main gun as some variants of the much larger Sherman tank, the M18 attained a much higher top speed of up to 55 mph (89 km/h) by keeping armor to a minimum, and using the innovative Torqmatic automatic transmission.

<span class="mw-page-title-main">75 mm gun M2–M6</span> Standard American tank guns of the Second World War

The 75 mm gun, models M2 to M6, was the standard American medium caliber gun fitted to mobile platforms during World War II. They were primarily mounted on tanks, such as the M3 Lee and M4 Sherman, but one variant was also used as an air-to-ground gun on the B-25 Mitchell medium bomber aircraft. There were five main variants used during the war: M2, M3, M4, M5 and M6.

<span class="mw-page-title-main">M4 Sherman variants</span> Tank variants of World War II

The M4 Sherman tank was produced in several variants, a result of mass production spread across several manufacturers and several years. It was also the basis for a number of related vehicles and Shermans have been modified by several nations, ranging from upgrades to complete hull conversions for another task. Originally designed in 1941, M4 variants were still used by Israel during the 1967 and 1973 wars with its Arab neighbors.

<span class="mw-page-title-main">Tanks in World War II</span> Overview of tanks in World War II

Tanks were an important weapons system in World War II. Even though tanks in the inter-war years were the subject of widespread research, production was limited to relatively small numbers in a few countries. However, during World War II, most armies employed tanks, and production levels reached thousands each month. Tank usage, doctrine and production varied widely among the combatant nations. By war's end, a consensus was emerging regarding tank doctrine and design.

<span class="mw-page-title-main">Heavy Tank M6</span> American heavy tank

The Heavy Tank M6 was an American heavy tank designed during World War II. The tank was produced in small numbers and never saw combat.

<span class="mw-page-title-main">Super Sherman</span> Medium tank

The Sherman M-50 and the Sherman M-51, both often referred to abroad as the Super Sherman, were modified versions of the American M4 Sherman tank that served with the Israel Defense Forces from the mid-1950s to early 1980s. The M-51 was also referred to as the Isherman. However, the nicknames "Super Sherman" and "Isherman" were never officially used by the Israeli Defense Forces.

<span class="mw-page-title-main">M2 medium tank</span> Medium tank

The M2 medium tank, officially Medium Tank, M2, 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 Second World War in Europe. Production was 18 M2 tanks, and 94 slightly improved M2A1 tanks, for a total of 112. Events in Western Europe rapidly demonstrated that the M2 was obsolete, and it was never used overseas in combat; it was, however, used for training purposes throughout the war.

<span class="mw-page-title-main">Post–World War II Sherman tanks</span> Medium tank

This article deals with Sherman tanks extensive use around the world after World War II and catalogues foreign post–World War II use and conversions of Sherman tanks and variants based on the Sherman chassis.

<span class="mw-page-title-main">Lend-Lease Sherman tanks</span> Medium tank

The United States provided tens of thousands of its Medium Tank M4, also named the Sherman, to many of its Allies during the Second World War, under the terms of Lend-Lease.

<span class="mw-page-title-main">76 mm gun M1</span> American tank gun

The 76 mm gun M1 was an American World War II–era tank gun developed by the U.S United States Ordnance Department in 1942 to supplement the 75 mm gun on the basic Medium tank M4. It was also used to arm the M18 Hellcat tank destroyer.

<span class="mw-page-title-main">Vertical volute spring suspension</span> Type of vehicle suspension system

The vertical volute spring suspension system is a type of vehicle suspension system. This type of the suspension system was mainly fitted on US and Italian tanks and armored fighting vehicles starting from throughout the 1930s up until after the end of the Second World War in 1945.

<span class="mw-page-title-main">Tanks of the United States</span> Tanks used or produced by the United States

The United States has produced tanks since their inception in World War I, up until the present day. While there were several American experiments in tank design, the first American tanks to see service were copies of French light tanks and a joint heavy tank design with the United Kingdom.

<span class="mw-page-title-main">Medium Tank M7</span> WW2 American tank

The Medium Tank M7, initially Light Tank T7, was an American tank, originally conceived as an up-gunned replacement for the Light Tank M3/M5 ("Stuart"). The project developed to mount the same 75mm armament as the M4 Sherman while retaining the light weight and maneuverability of the M3 Stuart; however, during development the weight of the prototype surpassed the US Army's standard for light tanks and crossed into the medium tank category and was renamed. The M7 had significantly less armor than the M4 Sherman, no greater firepower, and held only a slight advantage in top speed. For these reasons, and because the M4 was already battle-tested and in full production, the M7 was cancelled in 1943.

<span class="mw-page-title-main">T25 Medium Tank</span> T25 Medium tank prototype

The T25 Medium tank was a prototype designed and tested in the United States, in 1944–45. A variant of an earlier series of prototypes, the T20/T22/T23, the T25 was conceived as a possible replacement for both the M4 Sherman Medium tank, and its previously proposed successor, the T23.

References

  1. "T23 Средний танк" [T23 Medium Tank]. aviarmor.net (in Russian). 2 September 2018.
  2. Steven J. Zaloga, Tony Bryan, Jim Laurier M26/M46 Pershing Tank 1943-53 Osprey Publishing p6
  3. 1 2 "Medium Tank T20 Prototype Medium Tank - United States". www.militaryfactory.com. Retrieved 20 November 2019.
  4. 1 2 3 4 5 6 7 8 Chamberlain & Ellis 1981, p. 149.
  5. 1 2 3 4 5 Chamberlain & Ellis 1981, p. 150.
  6. 1 2 "T23 Medium Tank". Tank Encyclopedia. 23 September 2016. Retrieved 20 November 2019.
  7. 1 2 3 Chamberlain & Ellis 1981, p. 151.
  8. 1 2 "T21 Light Tank". www.historyofwar.org. Retrieved 20 November 2019.

Sources