Saturday 2 April 2016

T2 Medium: Scaling Up

Starting with the M2 Medium Tank, American medium tanks were based on the M2 Light Tank. The method of their creation was as follows: novelties were tried out on a light tank, then the tank was proportionally scaled up in size. Of course, many changes were introduced into the design, like increasing the number of bogeys or return rollers. Overall, this method was successful. However, this was not the first attempt at using this method by American tank designers. The first time they tried it, they got something different...

Choosing Concepts

American tank production began with foreign tanks. This approach was the most correct during the war, as it saved the most precious resource: time. This way, by the end of WWI, the American army ended up with M1917 light tanks, reworked French Renault FTs, and heavy Mk.VIII International tanks, made in the likeness of British heavy tanks. The latter were built using American components, most importantly, Liberty L-12 engines.

The issue with medium tanks was never resolved. By the end of WWI, the Entente only had a Medium Mk.A Whippet in this category, an example hardly worth following. The Medium Mk.A didn't survive for long, and the Mk.B and Mk.C that replaced it were more similar to the heavy "rhombus" tanks.

As for the Americans, they placed their bets on John Walter Christie. In April of 1921, the M1919 Medium Tank entered trials. On one hand, it was a very progressive design with a very powerful 6-pdr (57 mm) gun and decent mobility for the time. In addition, it was the first successful convertible drive tank.

On the other hand, only the central bogey actually had a suspension. As a result, driving off-road was torture for the crew. There were also problems with Christie's engine. A request was made to rework the tank, especially the suspension. Christie interpreted the request in a peculiar way. He did rework the suspension, but the tank turned into an SPG. This forced the military to say goodbye to Christie, but as it turned out, not for long.

In parallel with Christie's tank, a program was launched by the Bureau of Ordnance in 1919 to develop a tank based on the British Medium Mk.D, an innovative design compared to its predecessors. The British didn't evolve to the point of rotating turrets yet, but the tank already had a classic layout. By December of 1921, the Rock Island Arsenal finished construction of the Medium Tank M1921. This was an impressive vehicle for its time, with fearsome armament, a rotating turret, and effective power of 10.7 hp per ton. The armour was also decent, reaching 25 mm in the front. The top speed of this 18.5 ton vehicle was 16 kph (to compare, the light M1917 could only reach a maximum of 14.7 kph, even after modernization).

Sadly, the engine caused delays in trials. The Medium Tank M1921 was later developed into the Medium Tank T1. Thanks to the more powerful Packard engine, the tank became a bit faster, and in January 1928 it was standardized as Medium Tank M1. However, by this point, it was already hopelessly obsolete.

It was obvious that the Medium Tank M1921 was headed for a dead end in the mid-1920s. Any improvements to the tank came at the cost of weight. The Bureau of Ordnance began a new project to design a tank in the 15 ton class. This project, indexed Medium Tank M1924, looked like a scaled down M1921. The turret remained, but there was also a gun in the front hull. On March 11th, 1926. the Ordnance Committee approved work on the Medium Tank M1924 in parallel with work on the Medium Tank T1.

Wooden model of the Medium Tank M1924.

The developer of the new tank was the Rock Island Arsenal. However, by fall of 1926, the project was sent to Maryland where the Tank Bureau was located. After a change of venue, the very concept of the tank began to change. As a result, nothing was left from the initial Medium Tank M1924.

Cutaway of the Medium Tank T2. As you can see, it has nothing in common with the Medium Tank M1924.

Bigger Copy

Harry Knox, the father of the T1 light tank series, took what would later become the Medium Tank Mk.I as a basis. This distant relative of the Medium Tank Mk.A Whippet had a front engine, but a rear transmission. As a result, the turret and fighting compartment were shifted to the back. Thanks to this layout, the vehicle was much shorter than the Medium Mk.D. At the same time, the weight was reduced.

Medium Tank T2 at the Aberdeen Proving Grounds, January of 1931. This was the original design of the tank.

The first American tank made in this image was the Light Tank T1. The prototype of the tank that was to become the main light tank of the American army was finished by September 1st, 1927. As a result of trials, changes were made to the design, resulting in an improved Light Tank T1E1 in early 1928.

This tank was used as the foundation for developing a medium tank. Fort Meade was chosen to develop this vehicle, indexed Medium Tank T2. Often, James Cunningham & Sons is credited with the development of the tank, but they were only the contractor who built it. The tank was designed by Harry Knox.

The tank as of May 1931. The T3E1 system was replaced with the T1 system with a short 37 mm gun and a counterweight on the gun mantlet.

Work on the new medium tank began in 1929, and an experimental prototype was ready by the end of 1930. The layout of the Medium Tank T2 was very similar to the Medium Tank Mk.I. The engien was in the front, shifted to the right, the driver was to its left. The transmission and drive sprockets were in the rear. The rear fighting compartment was roomy enough for the crew to not feel like sardines in a can. A large two-piece hatch was installed in the rear for crew entry and exit. The crew was less numerous than in the British equivalent. While the British tank had 5 crewmen, the American one only had 4: commander/gunner, loader, second gunner, and driver.

The tank lost its T1 system in the summer of 1931. Instead, a machinegun mount was placed in the hull, but no machinegun was ever added there. The amount of fuel tanks increased to two.

This was the end of the similarities between the tanks. Its suspension had nothing in common with that of the Medium Tank Mk.I, and was a further development of the Light Tank T1E1 with 12 road wheels and 4 return rollers. The hull and the track links, widened to 381 mm, were also inherited from the Light Tank T1E1.

The Medium Tank T2 was a much better design than its older brother. The small size and compact layout of the T1E1 made life difficult for its crew. This was especially true for the driver, who was forced to operate the tank with his feet wrapped around the engine. In the medium tank, the engine was covered with a bulkhead. The air filters were inside the fighting compartment, which made servicing them easier.

The 12 cylinder Liberty L-12 was used as the engine, with its power reduced to 318 hp. Thanks to such a powerful engine, the tank had impressive effective power: 22.4 hp/ton, a decent figure even in our time. The front armour of the 14.2 ton tank reached 22 mm. This was enough to protect the tank from small arms and light machineguns. Placing the fuel tanks in special containers outside of the fighting compartment was a good move.

The box on the right side was made for the radio.

The issue of armament was solved in a very interesting way. The main weapon of the tank was a 47 mm gun in the turret, based on the 37 mm AA gun, developed by Browning since the early 1920s. Like the AA gun, the 47 mm gun was fed with 5 round clips. A Browning M2HB machinegun was paired with the gun. This combination was enough to deal with any tank that existed at the time. However, this was not enough for the creators of the Medium Tank M2. They installed the T3E1 system to the right of the driver with a 37 mm semi-automatic Browning gun and a Browning M1919 machinegun. This gun also used 5 round clips.

Road to Nowhere

The experimental prototype of the Medium Tank T2 arrived at the Aberdeen Proving Grounds in late December of 1930. Mobility trials began that same month. Overall, the tank was very modern, and suited for mass production. However, the United States was hit with a financial crisis in 1929, which had a serious impact on the defense budget.

The last modenization of the Medium Tank M2, January 1932. The long object under the right fender is the exhaust pipe.

There was another problem. On January of 1931, in Rahway, New Jersey, a public demonstration of the Christie M1931 Medium Tank was held. The new tank was only inferior to Knox's design in armament, but this wasn't a big factor. The 37 mm M1916 gun and M1919 machinegun on the tank was enough for the military. The Christie tank surpassed its competitor in all other parameters. The same Liberty L-12 engine allowed it to reach unseen speeds for the time. On wheels, the difference grew even more. Christie's design was a huge step forward, and the Medium Tank T2 looked like a relic in comparison.

A large hatch in the rear was used for the crew to enter and exit.

Despite the appearance of such a dangerous competitor, the Department of Ordnance continued the trials of their tank. The trials revealed the same problems as the Light Tank T1E1 had: the front engine limited the driver's sight. Problems with the suspension cropped up. Theoretically, the tank could reach a speed of 40 kph, but in practice, it could only drive at 32 kph, as the suspension began to fall apart at higher speeds.

Problems with the armament were also discovered. The 47 mm gun was unbalanced. To solve this problem, counterweights were installed on the gun mantlet. Around this time, the T3E1 system was removed, replaced with the T1 system: a 37 mm gun M1916 gun.

Interior of the Medium Tank T2. The conditions were very comfortable for a late 20s tank.

After the mobility trials, the tank was sent away for improvements, returning to Aberdeen in January of 1932. By then, the T1 system was removed, and replaced with a ball mount for a machinegun. The main armament in the turret was also removed. One of the novelties was a new type of track link, similar to the one on the Medium Tank Mk.II. A mount for an AA machinegun was also added. Sadly, these additions made no difference.

The problems with the suspension were not solved. In addition, changes to the turning mechanisms were needed. Even though the Bureau of Ordnance considered the Medium Tank T2 the best available tank, it was obvious that pushing through their design wouldn't happen. At that point, the budget could only cover three Christie Medium Tank T3 and four Christie Combat Car T1. To sell them, Christie was ready to make them with no engines or armament. They would be installed by the military. It could only afford 6 T1 systems, so one Christie Combat Car T1 was armed with a machinegun.

Tanks of the 67th Infantry Company, Fort Benning, 1932. Staff of the Bureau of Ordnance could not have through of better advertisement for Christie's tanks.

The last attempt to push the Medium Tank T2 through was made at Fort Benning, the center of infantry tanks at the time. The tank was included in the 2nd Tank Company, reformed into the 67th Infantry Company in October of 1932. The company also had T1 light tanks, the experimental Medium Tank T1E1, and three Christie Medium Tank T2.

American congressmen periodically visited this unit. Representatives of the Bureau of Ordnance expected a demonstration to move things forward. The result was the opposite. A comparative demonstration of their tank against Christie tanks was the worst thing they could have thought of. Even a layperson could see which tank was better. Fort Benning became the swan song for Cunningham tanks.

In the late 1930s, the Medium Tank T2 was sent to Aberdeen, where it remained in the Museum of Armament. Several years ago, the tank was sent to Fort Lee, where a new museum was planned. Sadly, the future of the museum is uncertain. The tank is rusting in Anniston, Alabama, awaiting restoration.

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