Light Tanks T1E4 and T2E1: Experiments on an Ideal Platform

The idea of a light tank with a front engine that the American Ordnance Department insisted on was at a dead end by 1932. Trials of the Light Tank T1 family and later the Medium Tank T2 showed that the idea was unacceptable. Poor visibility, excessive mass, bad crew conditions, and, most importantly, the limits of further development, put an end to such tanks. Designers moved on to working on other tanks with different layouts. Harry Knox, the father of the front engine American tanks, did not abandon his idea, and kept looking for a place for his idea. Stooping down to plagiarism, he crossed his Light Tank T1E1 with the Vickers Mk.E, its overseas competitor. The resulting "hybrid" Light Tank T2E1 was not that bad.

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.

Original article by Yuri Pasholok.

World of Tanks History Section: American Pre-War Tank Building

At the end of the 19th century, the United States of America began a sharp rise in the development of industry, science, education, and culture. The army and navy guaranteed protection from any opponent in the New World, and the oceans around North America acted as the most effective border guard against any transoceanic enemy.

Externally, the US practiced isolationist policies and kept far away from the wars that engulfed Europe. However, when WWI started, the situation changed. After a series of incidents that resulted in losses of American merchant vessels, President Wilson asked Congress to enter the war. On April 4th, 1917, the Senate allowed the United States to join the First World War.

On June 13th, 1917, General John Joseph Pershing and the first American expeditionary force arrived in Europe. This commander previously fought in local conflicts with the Apache and Sioux, in the Hispano-American War of 1898, and Pancho Villa's rebels. The positional war in Europe was somewhat different from what the American military imagined it to be, and Pershing understood the importance of an army that could deliver a powerful strike while remaining mobile. It is not surprising that he initiated the creation of armoured forces in the United States.

On January 26th, 1918, the American Tank Corps formed from two parts: the tank corps of the American Expeditionary Force in Europe and the Tank Force of the National Army, later renamed the Tank Corps of the National Army.

Proposals for armoured vehicles were sent to the American army before. In 1915, a businessman named Lowe proposed a 30 ton tank project based on the Willoc tractor. In 1917, the Holt tractor company proposed a vehicle that looked very similar to the British "Little Willie" tank, created by William Tritton.

Another interesting project was proposed by the Pioneer tractor company in Minnesota. The vehicle was nicknamed "Skeleton", due to its suspension. The tracks of the Skeleton were not attached to the hull, but to a metal frame with pipe connectors. A small rectangular hull, designed for two crew members, was located between these frames.

The military's lack of enthusiasm towards American tanks led to the necessity of purchasing foreign vehicle when General Pershing ordered the creation of a tank force. On September 12th, 1918, the American tankers fought their first battle at Saint-Michelle, a village south of Verdun. Lieutenant-Colonel Patton commanded the 344th and 345th tank battalions in this battle.

American armoured doctrine used small, light, medium, and heavy tanks. The battle-proven French Renault FT-17 was chosen as the light tank. This 6-ton vehicle was one of the most advanced in the world. The layout of the FT-17 was later accepted as classical: the armament was located in a rotating turret, engine in the rear, crew compartment up front. Initially, the Americans planned to order 3500 vehicles of this type. Some of these were to be built by the French, and some by the Americans. The Ford company purchased a license to manufacture these tanks.

American engineers altered the design of the tank. The driver's visibility was improved. Armour was increased. The Renault engine was replaced with an American one. The American version of the FT-17 was indexed M1917. The tank was armed with either a 37 mm gun or a machine gun.

Heavy tank units were to be armed with the jointly developed British-American Mark VIII Liberty tanks. This tank was a typical "rhombus" type, with fairly wide tracks, enclosing the entire hull. The vehicle weighed 39 tons, and was armed with two 57 mm Hotchkiss guns, with 5-7 rifle caliber machine guns for support. The 10-meter long tank was crewed by 8-11 people

The Liberty was the peak of British rhombus tanks. Perhaps, this direction could be developed further, but, as soon as the FT-17 was deemed superior, the time of the rhombus came to an end.

The Mk VIII did not fight in WWI. The Americans built about 100 of these vehicles in 1919-1920. Until 1930, it remained America's only heavy tank.

After WWI ended, large tank units proved too expensive for the USA, and, in 1920, the tank corps was disbanded. Over the next 20 years, the US did not have large tank units, but funding was periodically issued for new vehicles.

For examples, in the 1920s, the army staff considered the M1917 obsolete, and initiated the construction of a new light tank. Specialists from the Rock Island Arsenal, along with engineers from the Cunningham tractor company, presented the T1 project in 1924. This small 7-ton tank had a non-standard layout, with a rear turret, and front engine. The tank was armed with a 37 mm cannon and 7.62 mm machine gun. Numerous modifications of the T1 project were developed over its lifetime, but they all had their flaws, and were rejected.

The last of the Cunninghams, the T1E4 and T1E6, were meant to solve the flaws of their predecessors. Elements of the British Vickers 6-ton were used in their construction. The engineers achieved superior mobility with the same armament, but there were serious problems with the gearbox and the tanks were not mass produced.

The Americans designed new light tanks for seven years after the termination of the Cunningham program. One of these tanks was the T2 Light on a Vickers suspension. It was designed with machine guns and small caliber autocannons for armament. The T2 was not mass produced, but its creation led to valuable experience, leading to a mass produced M2 Light tank with a new suspension and machine gun armament. On December 29th, 1938, the Americans accepted and began production of a new M2A4 light tank. This tank was armed with a cannon. The new vehicle was maneuverable, and had armour comparable with American medium tanks of the time. Mass production of the M2A4, in which the Americans experimented with cast hulls and turrets, never got off the ground. Welding and riveting of armour continued until the spring of 1941.

In parallel with the T1 tanks, the Americans were developing a medium tank, superior to the Liberty in mobility, and to light tanks in protection. The new tank would have been indexed M1921. It weighed 23 tons, and was armed with a 75 mm howitzer in a rotating turret. This howitzer was capable of not only immobilizing, but completely destroying, a light tank with a direct hit. This was demonstrated practically, using poor M1917 tanks as targets. After 7 years of development, the vehicle was not mass produced due to high cost.

In parallel with the T1 Medium, another lighter medium tank was developed, the T2 Medium. It was built by the Cunningham company using the same layout as the light T1. The tank could accelerate up to 25 mph, and was armed with a 37 mm or 47 mm gun, and machine guns. The T2 Medium was the best tank developed by the Bureau of Ordnance. And yet, it was too expensive for an America that was struggling with the Great Depression.

The Great Depression led to a reconsideration of many principles of armoured warfare. Tank units were to be armed with light, mobile, and cheap vehicles. Engineer Christie proposed some projects, but the military's response to his convertible designs was rather unenthusiastic.

By 1934, Christie annoyed the military so much, that they were ready to accept anything, as long as they didn't have to deal with the persistent and rude engineer. In April of 1934, Captail Reiry proposed a tank project using the Christie chassis and 4 machine gun sponsons, along with a 37 mm gun in a rotating turret. The Bureau took the opportunity to reject the Christie suspension, and instead take a recently developed suspension unified with the T2 Light tank. The resulting vehicle was indexed T5.

After many modifications, the tank was built in December of 1937, with a wooden turret. In about a year, the tank received a real turret, and was sent to Aberdeen.

The T5 was protected by 25 mm thick armour, and propelled by a Continental air cooled engine, which allowed it to reach a speed of 31 mph on a highway. The armament included a 37 mm gun an several machine guns. The tank's turret and sides had openings for the crew's pistols.

In the summer of 1939, the tank was accepted under the index M2. The vehicle was produced in Rock Island.

The beginning of WWII in Europe forced the American government to reconsider their priorities for armoured forces. It was no longer a guarantee that they could sit this one out, and development of a better tank began. This resulted in the M3 tank being developed in the summer of 1940, but that is another story.

Original article available here.

Christie's Victim

The 1920s were a dark time for tank builders worldwide. The rapidly changing role of tanks and a harsh cut in finances meant that less than a thousand tanks were built worldwide. The majority of these tanks were MS-1s, all while the Soviet Union was still reeling from WWI and the civil war. Britain saw the creation of the successful Medium Tank MkI and MkII, as well as tankettes, but a low budget was a significant hurdle. The French limited themselves to modernizations of the Renault FT, and these tanks, known as Renault NC, were built for export, instead of the French army. Germany quietly worked on their tanks. The US was the least lucky of all. Despite a wide program for new tanks, not a single vehicle designed in the 1920s in the United States was put into mass production.

Do It Yourself

After WWI, the American army obtained almost a thousand light 6 ton M1917 tanks and a hundred heavy Mk.VII International. The light tanks were the more important acquisition. The problem with it was that the Renault FT, the ancestor of the M1917, was built for the European theater of war. Its top speed was only 8 kph, and while a superior engine made the M1917 slightly faster, it was still inadequate for American needs.

In addition, tanks could travel a little over 100 kilometers before needing extensive repairs. They had to be transported to the battlefield on trucks. An attempt was made to solve the speed problem with the 100 hp Franklin 145 engine, which increased the speed to 14.5 kph. Further improvements were limited by the suspension. Only 7 tanks were modernized to the M1917A1 standard.

Seeing that the M1917 has little room to improve, the military put its bets on John Walter Christie. Sadly, the M1919 Medium Tank did not meet expectations. This tank that saw trials in April of 1921 was much more promising. It had a 6 pounder (57 mm) gun and could reach a speed of 20 kph on wheels, impressive for the time. A drawback was that its top speed on tracks was only 11 kph, and it only had a sprung suspension on the middle bogey. As a result, Christie altered the M1919, turning it into an SPG. The military tried to do something with this design until June of 1924, at which point it was obvious that the tank was a dead end. By time time, Christie had a falling out with the Bureau of Ordnance.

The Bureau saw that it had to make its own tank by the spring of 1922. According to the accepted norm, the 5 ton tank had to have a crew of two and be armed with a 37 mm gun and 7.62 mm machinegun. The armour had to be enough to protect it from rifle caliber armour piercing bullets. Its speed would be 19 kph and range 80 km. Nevertheless, work did not start until 1926. Until then, medium tanks were prioritized, with the expectation that once production was underway, light tanks would no longer be necessary. This cockiness was caused by early successes with the M1921 medium tank.

By early 1926, it was obvious that work on the M1921 stalled. On January 26th, 1926, the OCM recommended that a new tank be designed. Initially, work started at the Rock Island Arsenal. According to archives, it was initially supposed to have a classic layout with an engine in the rear. However, on September 1st, the department was moved to Fort Meade, Maryland, home of the Tank Department.

Harry Knox's Project

One man is worth mentioning, as he directly impacted what the new tank would look like. Harry Austin Knox is more known to automotive historians. For a quarter of a century, Knox successfully dealt in cars and trucks. Knox took up tanks in 1924, when the military had its row with Christie. Knox became the father of the new tank that was designed at Fort Meade.

He decided to discard the classic layout. The basis for his design would be the British Medium Tank Mk.I, which was initially considered a light tank. The drive wheels were in the rear, and the engine in the front. As a result, the tank was a lot shorter than the M1917, but the driver was unlikely to be very happy about this decision. The driveshaft went between his legs, and the driver was left almost spooning the engine. This also caused the tank to have a very long "nose", which negatively impacted the driver's visibility. The gearbox wasn't lonely either, as it acted as a mount for the driver's seat. The suspension was similar to a tractor's, but used skeletal tracks. The same tracks were designed for the Medium Tank Mk.I and were far superior to those of the M1917.

On September 26th, 1926, a technical committee reviewed both types of tanks and selected Harry Knox's design. The front engine resulted in better balance. By March 15th, 1927, the tank was at the stage where it was time to pick a contractor. James Cunningham & Son Co. won the tender. On one hand, the company had no prior military contracts, and its main product was light cars. On the other hand, Cunningham had serious industry experience: in 1916, it was one of the first to produce the V8 engine.

On April 12th, 1927, James Cunningham & Son Co. received a contract for the production of an experimental light tank. 120 days were allotted for this task. Work finished by August 1st, and on September 1st the newly indexed Light Tank T1 was shown at a demonstration in Rochester. At seven tons, it was heavier than the M1917, which only caused more problems with transporting the tank by trucks. The armour was even thinner than on the M1917 at less than 10 mm. This was not enough for an infantry support tank.

On the other hand, the engine was very impressive. The 110 hp V8 engine gave the tank an impressive power of 15.7 hp/ton. A powerful engine didn't help the M1917A1 due to its suspension, but this was not so with the T1. Its maximum speed was 28 kph, an impressive figure for the late 1920s. The experimental tank had a dummy turret platform and turret.

After trials at Aberdeen, the T1 tank was converted to the Cargo Carrier T1. Its trials also went well, and a green light was given to both the light tank and the cargo carrier. An order was made for 4 T1E1 tanks and 2 T1E1 cargo carriers. The fuel tanks were moved from inside the hull to containers above the tracks. In addition, the front section of the tank was shortened. The cylindrical turret got a 37 mm M1916 gun and a coaxial Browning M1919 machinegun.

Despite a series of drawbacks, the infantry was amazed by this new tank. Even before the T1E1 was built, Major General Robert Allen insisted that it be standardized under the index Light Tank M1. This index lasted from January 14th to March 30th, 1928. The Secretary of War cancelled the standardization, remarking that it would be prudent to first wait for performance data from trials.

In June of 1928, four T1E1 tanks were sent to Fort Meade for trials. Here, they were included in the 4th tank company along with M1917 tanks. Joint maneuvers proved that these tanks were superior to their predecessors.

Trials held in October of 1928 were even more impressive. Three tanks and two cargo carriers drove from Fort Meade to Gettysburg and back. The T1E1 achieved an average speed of 16 kph, unthinkable with the M1917. One T1E1 was sent to the Aberdeen proving grounds, where it travelled 3232 km over 57 days without serious breakdowns. This was a phenomenal result, as a M1917 tank would have fallen to pieces by then. It seemed that everything went smoothly and a contract for 200+ T1E1 tanks would soon follow.

Christie's Doombringer

Unexpected problems came up. On November 19th, 1928, an unusual vehicle set out from Fort Meade. It looked more like a race car than a tank. This vehicle was the Christie M.1928, an experimental tank made by Christie's new US Wheel Track Layer Corporation. The designer called his creation M.1940, implying that these tanks were the future. The main feature of the tank was an independent spring suspension, today known as Christie springs.

The route of the M.1928 repeated the route the T1E1s took a month earlier, but the result was vastly different. Christie's tank showed an average speed of 45 kph; the maximum speed on tracks was 68 kph, and on wheels 112 kph. This was a shock for the T1E1. The biggest problem was that Christie's tank didn't need trucks to transport it to the battlefield, and had a far superior range compared to its competitor.

Knox and Cunningham's tank paled in comparison. Mass production of the T1E1 was forgotten, especially since complaints about thin armour didn't go anywhere. In late November, a request was made for a modernized tank.

Playing Catch-up

Work on the T1E2 dragged on, and it only appeared at the Aberdeen proving grounds on June 3rd, 1929. Thickening the armour to 15 mm was not enough. The mass grew to 8.8 tons, and it was time to change the suspension. The tracks became an inch wider. The engine was upgraded to 132 hp, raising the effective power to 15 hp/ton and the maximum speed of 29 kph. These were good characteristics, but even the new T1E2 was not up to par with the Christie tank. On the other hand, Christie's design was more of a testbed, and the T1E2 was a complete tank. The new modification had a new turret with a 37 mm semi-automatic Browning gun.

Major General Allen insisted on standardization of the T1E2, but the Commander of the Land Forces Major General Summerall was against the idea. First of all, he received troubling news from infantry and cavalry representatives who were watching Christie's demonstrations. Second, the T1E2 was simply not the tank that Summerall wanted in his army. The tank was cursed with mechanical problems. The suspension was a big contributor, as the increase in mass made itself known. Strong vibrations made aiming and firing on the move difficult. Additionally, the idea of a front mounted engine was declared unsatisfactory.

A modernization of the second T1E1 prototype, known as the T1E3, attempted to resolve these problems. The new suspension had four bogeys, the first three with hydraulic suspensions, and the last one with a spring. The tank received an engine and armament equivalent to the T1E2. The maneuverability and smoothness increased, but it was too late. It was April of 1931, and already three months since Christie personally drove his M.1931 in front of numerous photographers and cameramen. The T1 family compared poorly.

The last chance for the T1 was abroad, especially due to the Great Depression that started in 1929 that dispelled all hopes of hundreds of tanks. This chance arrived in 1930, when a Soviet commission arrived in the United States, led by UMM chief I.A. Hhalepskiy. However, the deal failed, which Halepskiy recorded in his report, dated June 6th, 1930.

"According to the approved program, we were to buy samples and obtain technical assistance for the T-1, E-1, and Christie tanks.

The T-1 and E-1 tanks produced by Cunningham appear to be small tanks. The design of the T-1 and E-1 tanks is worse than the same type of tank we already bought from Vickers, namely their speed if 8 kph less, armour is ordinary, engine is water cooled (Vickers is air cooled), the final drives heat up, the track is so massive that it impedes required speed.

At the same time, the tanks cost 17.5 thousand roubles each, more than Vickers tanks. This is completely unacceptable financially. The company demands 50% up front and 50% on delivery, and demands that at least 50 tanks of one type be purchased. The company refuses to provide any kind of technical assistance or to let our engineers into their factories.

The aforementioned details make it impossible to purchase this type of tank."

What happened next is well known: the commission examined Christie's tank and ordered two vehicles, as well as the patents and a production license. Later, these tanks became the foundation for the BT-2 tank.

SPGs on the T1 chassis deserve a special mention. In 1928, one T1E1 cargo carrier was converted to a platform for a 107 mm (4.2 inch) mortar. A carrier on the T2 chassis, which used T1 components, proved superior. After trials of the chassis made as a laboratory for various suspension components, it was adapted as a carrier for the new 75 mm M1 howitzer.

The vehicle, created in 1930 and indexed T1 HMC, was superior to its light SPG predecessors. It weighed a little over 5 tons and was equipped with an 89 hp LaSalle engine. Its top speed reached 32 kph. Thanks to a superior suspension, its travel was smoother than the T1's. Trials showed that it was a perfectly suitable light gun carrier, superior to its tractor predecessors, but sadly, work did not continue past a prototype.

Original article by Yuri Pasholok.

World of Tanks History Section: Fury, the Tank that Knox Built

The M4 Sherman medium tank was a real workhorse of the American army. Its M4A3E8 modification, nicknamed "Easy Eight" by the tankers, was the pinnacle of this family of tanks.

The creator of the tank was the talented, but largely unknown engineer Harry Oxford Knox. His vehicles dominated in American tank development for over ten years! Who was he, and what did he contribute to the American tank school of thought?

Before the Tank

Harry Knox was born on January 19th, 1875, next to Westfield, Massachusetts. He graduated from the Springfield Technical Institute in 1894. Knox was obsessed with cars, and built his first gasoline engine in that year. Initially, Harry worked at the Overman Bicycle Company, where he made engines for three-wheeled cars. Later, he decided to start his own business.

In 1900, the Knox Automobile Company was formed. At first, Knox made three-wheelers, but later he switched to four wheel cars. From 1906, his company also produced fire trucks. The company made passenger cars until 1914. The production of trucks lasted much longer, until 1927, when the company ceased to exist. Some of its products survived to this day.

Car to Tank

Some sources mention that Harry Knox took up tank design, but few mention how deeply he delved into it. His work for the military began in 1924. At the time, the American Ordnance Department burned its bridges with John Walther Christie, another tank designer that rose from the car business.

Unlike Christie, who was difficult to work with and frequently drew the attention of the press to himself and his vehicles, Harry Knox was not a public man. As mentioned above, even some tank historians have not heard his name. Nevertheless, this unknown car designer was a key figure in American tank building.

His influence can be seen by looking at the patent bureau archives. The famous rubber-metallic track link, a suspension using volute springs, a single block front transmission used on American tanks for over 10 years, all of these things were thought up by Harry Knox. He had nearly a hundred inventions to his name which were used in American tanks and half-tracks.

Knox didn't just patent components, but entire tanks. For instance, Knox was the author and owner of the T1 Cunningham patent. Cunningham was just a subcontractor of the Ordnance Department. Christie looks like a nobody next to Knox and his inventions.

Left in Shadow

Why is this man unknown? This question is answered by any of Knox's patents. They all begin with the disclaimer that the invention is created for the government, and can be used with no limitations. Knox was left in the shadow of his patrons in the Ordnance Department.

The inventor had a sufficient salary, plus he likely received generous bonuses. On the other hand, the Ordnance Department was rid of the headaches that come with invention due to a "court" inventor that, unlike Christie, didn't hound them for royalties. By the way, one of Knox's patrons was John Christmas, a man that played a key role in the exile of Christie and his tanks from the American army in the early 30s. Christmas is even listed as a co-author in several of Knox's patents.

Having such powerful patrons, the inventor didn't need to worry about competition. Yes, Knox's T1 tank and the T2 medium built on its basis lost to Christie's M1928 on all fronts, which appeared at the worst possible time. Christie's tank ruined the planned purchase of 250 T1s, and Knox had to radically redesign his vehicles. This resulted in light T2 and T5 tanks, which became the basis of nearly all American tank development from 1935 to 1945.

Light M2, M3, M5, medium M2, M3, M4, M7, the heavy M6, and even the superheavy T28, all of these tanks were made with suspensions and other components designed by Knox. His idea of a bogey with a rubber-metallic track was used on American halftracks. Knox's designs were also used by the Marmon-Herrington company, including the M22 Locust.

Knox's fame started to wane in the middle of the 1940s, when it was clear that his designs were obsolete. Torsion bars replaced springs, the transmission was moved to the rear of the tank. This change was partially influenced by the KV-1 tank, which was sent to the US in the fall of 1942 for trials. Knox's last patent is dated 1951.

The star of American tank building died in 1957, leaving his mark in history as only the creator of one of many car companies. Harry Knox's tank legacy awaits its researchers...

Article author: Yuri Pasholok

Yuri Pasholok is a historian, a specialist in the area of WWII armoured vehicles. He is the author of countless articles in various publications related to tanks, as well as the books Panzerkampfwagen Maus and Stalin's Steel Balls. He is also a historical consultant for World of Tanks.

World of Tanks History Section: T1 Cunningham

At the start of the 20th century, no one could have predicted that tanks would become an army's main strike force. Tanks were expected to support infantry, cover advancing soldiers with their armour, and help them suppress the enemy. Fortifications that were too tough for the tanks would be destroyed by artillery, shooting from prepared positions.

In the middle of the 1920s, American high command admitted that the M1917 tank currently used by the army was obsolete, and created a plan for the development of a superior fighting behicle. In 1924, the head of the commission was sent to Rock Island to aid in the creation of a light tank, no more than 5 tons in mass.

In cooperation with engineers from the Cunningham company (famous for its tracked tractors), the military, armed with experience of their foreign colleagues (mostly the British engineers responsible for the Medium Mk II), came to the decision that the classic tank layout is not ideal. After uniting American and foreign solutions, the T1 tank prototype was born. Tests of the chassis showed that it needs to be heavily reworked; the "tractor past" was no longer enough. The new high-tech chassis let the tank accelerate up to 29 kph, a record among similar vehicles. Sadly, this could not be repeated in combat conditions, as the chassis performed poorly on cross-country terrain, bomb craters, etc.

The chassis consisted of 16 small diameter wheels, 8 per side, with spring amortization, 6 supporting rollers, a front idler wheel, and a rear drive wheel. The tank hull was made of partially welded and partially bolted together armour plates 10-15mm thick. The transmission and 8 cylinder gasoline engine were in the front. The engine was capable of 132 hp at 2600 RPM. The tank had a 58.5 gallon (221.5 liter) gas tank, and a 4 speed gearbox. The engine was started electrically. The driver's compartment was united with the fighting compartment, in the back of the tank. The T1's crew consisted of two members: the driver and commander (who doubled as a gunner).

Armament was installed in the turret only. It consisted of a 37 L/50 M5 37mm gun, with 104 shells (some sources claim 80), and a coaxial M1919A4 Browining machine gun (with 3000 rounds). Despite the small caliber of the main gun, the muzzle velocity of 777 m/s allowed it to penetrate any currently fielded armour at 1000 m.

The T1 light tank was worked on through 1926, and a prototype was handed to the military in early 1927. Field tests were disappointing. The prototype had poor mobility, could barely cross a trench two meters across, and the stiff suspension made firing on the move difficult. After modifications, the T1E1 was accepted by the military in 1928, as the M1. 4 tanks were sent to the 4th Tank Company (Fort Meade, Maryland), where they tested extensively through 1930. After these tests, the T1E2 modification was equipped with a more powerful engine, a modified turret (without a slanted armour plate) and thicker front armour. The tank was later equipped with a longer 37mm gun.

The last modification was the T1E3, with a spring suspension and a long barreled gun. Nevertheless, due to many design drawbacks, mass production of the T1 light tanks never got off the ground. The only known T1E1 is displayed at the Aberdeen tank museum.

Original article available here.

Christie Tank Trials and Foreign Interest

It's no secret that the Soviets were very interested in Christie's tanks, but so were lots of other people. Here is a translation of a dialogue between several American officials, sent by Stalin to Kirov (RGASPI 558-11-746). The document covers foreign interest in the Christie tanks, and then discusses their trials in depth. A great depth. Maybe too great (it's really, really long).

"Barbour: I presume that he sold two tanks to the Russians because we bought only one tank instead of six.
General Hoff (chief of armament): I know that he sold two tanks to the Russian government, but I don't think it has anything to do with our contract. It is likely that he sold two tanks because we only bought one.
Barbour: He told me that if we bought six tanks, he would not sell two to the Russians. He said that the tanks were present, and available for inspection if we wanted to buy. I think that, if these tanks really had something to offer in the area of high speed tanks or vehicles, we should not have allowed foreign governments to purchase them before we had a chance to test. If these tanks cost us $250,000, let's make sure that this sum was not spent in vain.
General Hoff: It would not have stopped him from selling tanks to other governments. He already sold one to the Japanese government.
Barbour: I don't know anything about selling a tank to Japan. He only told me about selling to Poland and Russia.
General Hoff: I think that the sale to Poland did not go through.
Barbour: I have also heard this.

Tanks in service

Barbour: Let us discuss the issue of tanks in service. Before we discuss this issue, I would like to ask a few questions. Tanks are used by infantry?
General Fuqua (inspector of infantry): Yes, sir.
Barbour: Then tanks are entirely commanded by infantry?
General Fuqua: Yes, sir.

Trials of Christie tanks

Barbour: Are you familiar with Christie tanks?
General Fuqua: Well familiar, sir. I was inside one during movement.
Barbour: Do you possess reports from infantry officers that tested this tank?
General Fuqua: We never tested the Christie tank. We tested the Christie chassis. The tank commission, combined with the cavalry commission, which was looking for a new chassis for armoured cars, gave a very good impression of it, which led to a request to purchase one or more. The request was approved, and we bought one tank. The tank cost $55,000. We still have not received it. I just received a letter that it will be ready by the end of the year (1930).
Barbour: Did you see any complete tank?
General Fuqua: No, sir, only the chassis that I reported on.
Barbour: What was the vehicle that was driving around?
General Fuqua: That was the chassis that I described. It was not an armed and armoured vehicle. We didn't test it personally, but I received a report from a tank expert that considers it promising.
Barbour: What of the tank that you had last year? The one that was used and shown off to everyone?
General Fuqua: I deem it good. I consulted both commissions and talked to all officers that had anything to do with tanks during the war. All unanimously agreed that the chassis should be developed into a tank, which is what we did.
Barbour: Did this support the purchase of 4 tanks that you received funding for last year?
General Fuqua: Yes, we recommended this.
Barbour: I think that General Williams recommended this also.
General Fuqua: In his report, he considered it necessary to buy four or five of these tanks for the final evaluation of whether or not they are useful to our goals.
Barbour: Do you know, and can you tell the committee, what has changed regarding this purchase?
General Fuqua: Yes. Plans changed, since Christie's tank is still untested. From the department of armament's point of view, it is more correct to purchase one tank and test it, instead of buying five or six tanks that might prove unsatisfactory. A decision was made to test one tank before buying the other five.
Barbour: Can the tests be fully completed with one tank?
General Fuqua: Mechanical tests can be completed.
Barbour: I understand that General Williams, claimed that at least four or five tanks are necessary last year.
General Fuqua: I do not think that complete tests can be performed with just one tank. The services that use tanks are mostly interested in methods of combating tanks. Future tanks will be very fast than tanks used in the world war. The issue of using these fast tanks is one of life and death. Tests like these cannot be performed with one tank. Five tanks represent a single tactical unit (a platoon) and issues of coordination between infantry and fast tanks can only be explored with the use of several tanks. These tests with infantry are much more important than mechanical tests. If the Christie tank is delivered and passes mechanical tests, it is necessary to, as soon as possible, purchase at least five additional units of this tank.
Barbour: So you consider it correct to purchase five or six tanks to test one tank?
General Fuqua: The chief of the infantry directorate expressed a desire for six tanks.
Barbour: Were the proposals announced?
General Fuqua: Yes, sir.
Barbour: And received?
General Fuqua: Yes, they were received.
Barbour: For six tanks. These proposals did not exceed the sum of $250,000, prepared for this matter?
General Fuqua: Correct, sir.
Barbour: You observed the Christie tanks. Were they a promising weapon?
General Fuqua: Very promising. However, at the end, we decided to purchase just one tank.
Collins: Did you make this decision when the war minister already made his?
General Fuqua: I did not know about this. Perhaps it was so. However, at the time, I was not aware of it, Mr. Collins, and agreed, since one tank is better than none.
Barbour: The plan changed after the tender was announced. The bids were received, after which it was decided to buy six.
General Fuqua: Yes, but after that, we held another meeting, where it was decided to buy one.
Taber: Is this tank complete enough that you can make a decision on whether or not it is reasonable to order a large amount of these tanks?
General Fuqua: Yes, sir.
Taber: This precise model?
General Fuqua: By the unofficial answer, this is exactly the tank that we desire to purchase.
Barbour: The trial tank had a powerful gun, didn't it?
General Fuqua: That was not a tank. It was just the chassis. I have never seen the tank. My report uses the report of an officer who has seen the tank.
Barnour: And the report is classified?
General Fuqua: The report was a personal memo, sent to me by an officer that was keeping track of the project. I have no objections to adding it to the minutes.
Barbour: Pass it here.

Report on the trials of Christie tanks

General Fuqua: With your permission, I will read the most important part of this note.

The officer spent several days at Rueil [Note: another possible mitransliteration. Original: Руей], starting from November 24th. He observed trials of two Christie tanks that were built for Russia. He personally rode in one of those tanks for 30 miles off-road. He found the travel to be light and gentle. The two tanks were attached together, with little difficulty. The tank could climb a 43 degree slope of liquid mud with no difficulty. The entire tank, with no turret, weighs 8 tons. The armour is composed of plates half an inch thick. The internal layer is composed of a soft steel, 3/16 of an inch thick. The proposed mass, with a turret, gun, crew, and armament is over 10 tons. The Russian tank, while moving on wheels, moves using a drive mechanism. The American tank uses a chain mechanism. The officer says that a drive mechanism will allow a much faster process of converting the tank from tracks to wheels.
Currently, Mr. Christie is building a tank for Poland. This tank is not the same as the one for Russia. I heard that the contract for that tank has been annulled. The tank would have been finished at the same time as the American tank. The officer considers that the American tank will be finished in about 3 weeks. It will be delivered to Fort Meade, and also to Washington, so interested parties may see it.
The tank is 5 feet tall without a turret, and about 7 feet tall with.
The officer points out that a lot of car factory representatives were present at the trials. All present rode the tank, and were impressed by the smoothness and lightness with which the tank crossed terrain, and had a very high opinion of the individual spring suspension, which, in their opinion, allowed the tank to move smoother than a car.
The officer points out that the Polish tank, without a buyer, can be sold to the government if such is deemed necessary and sufficient funding is provided.
Barbour: Do you know how the Russian government managed to purchase such a tank?
General Fuqua: No, sir.

Trials of Christie tanks show its superiority to other types of tanks

Barbour: And so, on the Christie tank.
Colonel Cooper (chief of the tank school): Yes, sir. In October of 1928, Mr. Christie delivered a tank chassis to Fort Meier. The tank commission, along with General Sammeral (former head of the general staff), General Wells, and many other officers, traveled to Fort Meier and observed the trials of the chassis. Trials revealed a stunning speed, off-road performance, and smoothness of travel, to the point that we immediately thought that we have received a vehicle that satisfies all of our requirements. We weren't interested in the ability to put any hull on that chassis. We did not care, since the smoothness of travel was achieved. We do not mind shaking on the move, but we do mind the negative effect that has on the gunner. When I first saw Christie's tank, I thought that it was a tanker's dream. General Wells asked Colonel Escridge, who was the chair of the tank commission, if it was possible to get Mr. Christie to let us put his tank through trials without paying for it, making any promises, or being responsible for damage it might suffer. I was tasked with preparing the contract and having it approved, which I did.
The contract freed the government of all responsibility in the event of damage to Mr. Christie's tank. Mr. Christie delivered his tank to the tank school, where we did things to it that we would never to do our own tanks, since it was still Mr. Christie's property. The tank had weaknesses, but these were mechanical weaknesses, and not at all caused by the design itself. Mr. Christie is not a wealthy man, and used his savings to perfect his vehicles. He could not afford to have first-class craftsmen do metalwork for him. The first problem occurred when one of the wheel prongs broke. The wheels travel idly. The front drive wheel, which pulls the tank, cannot function. There were first two of these prongs, but one broke after a sharp turn. We examined it, and turns out there was a crack in a cast round part. If Mr. Christie had the means, this part could be forged. Such a breakdown would have disabled any other tank in our possession. Captain Tarp took off 8-10 track links and the tank was able to drive back to the repair base. Any other tank would have to have its tracks removed completely, and drive back to base on wheels.
Shall I continue?
Barbour: Yes, this is very interesting.
Colonel Cooper: These tanks represent a strategic reserve of the general staff. In other words, if a section of terrain is discovered that is suitable for using tanks, they will be assigned to aid an offensive. The tanks we had previously would have to be taken there by railroad, or with special heavy trucks. Our light tank regiment has 223 light tanks, and we would need 223 trucks capable of carrying 8 ton loads. These trucks cost $8000. The trucks would cost $1,800,000, and make an additional 223 engines that we have to care for in the field. This makes supplying the unit difficult, and makes operating the unit more complicated from a mechanical point of view to the point where we recoil in horror at the though that a war might start before our logistical system can satisfy our needs. We have witnessed that the Christie tank moves perfectly on rubber wheels. Mr. Christie made four or more trips between the Meade and Roway camps on wheels. If I am not mistaken, that is 1200 or 1400 km that the tank traveled on wheels. Tanks could be positioned 80 km behind the front lines. They are sent forward by road so that they can enter the battle at the right time. This distance takes 2.5 hours. This way, if we move at night, we can deliver the tank to its mission start on wheels, and then switch it to tracks. This job can be done by two people in a relatively short amount of time.
The tank will be equipped with armour that satisfies our requirements. Of course, we won't cross reasonable boundaries, but since tanks will be the first to assault the front lines, they must be armed accordingly. I am of the opinion that the Christie tanks offer us this possibility. I do not, by any means, think that Christie tanks are perfect, but I think that the suspension provides for an excellent gun platform, with which the gunner never needs to take his eye off the sight. I think the tank will double our offensive capability. At the time, we open fire at 400 yards. I know that the English teach to open fire at 1200 yards. If we fight a war with the English, and their tanks open fire at 1200 yards against our 400 yards, the result is obvious.
Barbour: Do you think that the Christie tank, in its current state, or in the state you saw it at the Meade camp, superior to the tanks we currently possess?
Colonel Cooper: Mr. Barbour, I will answer without hesitation that the vehicle is superior to everything we have in that field, or that we had in the past 10 years. It is beyond compare.
It is important to keep in mind that the army does not need a large amount of tanks, but in the last 12 years, we sat by an waited for a perfection of this weapon that would allow us to study it. We can theorize as much as we want, but that will be fruitless until we practically see how it behaves in battle, how we can supply it with fuel and ammunition, how to keep in contact with it. For 12 years, we have waited to begin this work, and we have not yet had a chance to begin.
Barbour: You spoke of mechanical defects. Are these serious?
Colonel Cooper: No, sir. Not one of them was serious. Christie periodically took his tank back, and replaced parts. Considering the materials that were used to make the chassis, this is the best possible job that could have been done by a man of his means. It is surprising that the tank continues to work after all we have done to it.

Trials of the Christie tank from Fort Meade to Gettysburg and back.

Barbour: The committee was informed that the trials involve 8 hours of movement on tracks.
Taber: I recall that the specifics were 8 hours to travel 320 km on wheels and 7 hours to travel 220 km on tracks.
Barbour: Is it not considered that there is no tank that can travel 60 km without breakdowns?
Colonel Cooper: I have seen such an assertion many times.
Barbour: What news do you have in that regard?
Colonel Cooper: The Christie tank left Fort Meade at 6:30 am and arrived at Gettysburg, a distance of 115 km, on wheels. The tank immediately left Getttysburg. It took 2 hours to return to Fort Meade, right on time for breakfast. It traveled for 2.5 hours on a concrete road, which is the toughest trial for a tank. The tracks on the vehicle were about 8 years old, since Christie was too poor to buy new ones. The tracks held. We only stopped once to fix them. We performed these trials on T1E1 and T1E2 tanks, and it took three days.
Barbour: Were there mechanical difficulties with the tanks?
Colonel Cooper: Yes, sir. We ended up having to load some of them on trucks. It was hopeless to try and make them move on their own power. These tanks look pitiful in comparison to Christie's.
Barbour: Allow me to pose a question. You insist that the tank seen at Fort Meade is superior to everything we have seen in that field. At the same time, you say that it is far from ideal.
Colonel Cooper: Yes, that is correct.
Barbour: Do you think that the army should continue trials of the Christie tank, with the goal of accepting it as a standard in the army?
Colonel Cooper: I am deeply sure of this. I am sure that we must continue this work. The changes Mr. Christie made that were recommended by the commission last year made the tank so reliable, that it can withstand trials you cannot even conceive of.

Characteristics of trials of the Christie tank

Barbour: You said that you did things to this tank that you would never do to your own possessions. What were the trials of which you spoke?
Colonel Cooper: We crossed swamps that none of our tanks could cross.
Barbour: How deep were these swamps?
Colonel Cooper: Deep enough that you could only see the driver's head. I estimate, about 4 feet.
Barbour: And the tank kept moving?
Colonel Cooper: Yes, sir. The tank moved as though it was on solid ground. We also drove at a reasonably fast speed through several logs positioned short distances apart. We wanted to see what would happen with the tank if it had to cross obstructions of this nature.
Barbour: What was the diameter of these logs?
Colonel Cooper: Most of them were 10, 12, or 13 inches in diameter. They were thick enough to throw the driver in the air in any other tank. The tank could also climb hills at a high speed that other tanks could barely climb at a low speed. It is obvious that you need a lot of force from the front wheels when climbing a hill like that. It is surprising that the tank was capable of it. Another trial, a jump at high speed. This happens when you drive to the end of a trench, jump, and then stop. The tank stops on the ground, several feet from where it jumped.
Barbour: How high did it jump?
Colonel Cooper: I think that the tank lifted 1.5 feet above the ground. It was not touching the ground at all, and came to a stop 8 feet from where it jumped.
Barbour: Do you think that the tank could jump while going up or down an incline?
Colonel Cooper: Yes, sir. For example, if the tank is driving on a flat surface, it can jump down, provided the height is not too great.
Barbour: How low can it jump?
Colonel Cooper: Not very. About 1.5 feet.
Barbour: But the vehicle you tested was not a tank, only a chassis.
Colonel Cooper: Yes, sir. When Mr. Christie took his tank from us in July, the infantry did not possess the means to acquire it, but cavalry had the means to acquire an armoured car or similar vehicle. That is when they took it from us, and presented it to the cavalry commission. Mr. Christie transported it to Newark and added some more armour. The tank used to weigh 5.5 tons, but now it weighed 8.5 tons. This was a tank in every way, except for its lack of turret.
Barbour: How heavy would the tank be with a turret and a gun?
Colonel Cooper: We expect the turret to add about 2 tons.
Barbour: So, 10 tons?
Colonel Cooper: Yes, about 10 tons.
Barbour: Is the tank designed to carry a gunner, and protect him?
Colonel Cooper: Yes, sir.
Barbour: And the driver also?
Colonel Cooper: Yes, sir.
Barbour: I understand that Christie is developing a new tank, 12-13 tons. Do you think that a heavier or a lighter tank is better?
Colonel Cooper: A lighter tank is preferable. Although, a difference of a few tons is not important. It is more important to consider the way these tanks are used.
Barbour: Can you use both samples?
Colonel Cooper: Yes, sir.
Barbour: You said that the Christie tanks provide smoother and lighter travel than old types of tanks?
Colonel Cooper: Yes, sir.
Barbour: Do you think that the tank you tested is a light tank, and can be used as such?
Colonel Cooper: In order to carry the additional weight of the gun and turret, Christie did what any engineer would do, and reinforced the chassis. As such, it is not correct to consider the chassis that we tested before. We will have a heavier chassis because it was modified to withstand a larger weight. We cannot, for example, put ton after ton on the same axle. We must increase the mass the axle can withstand.
Barbour: So, we must add the weight of the turret and such, and add the weight of the reinforced mechanisms?
Colonel Cooper: Yes, sir. I think that the issue was very well resolved. Captain Tarp can tell you more on this subject, since he spent 4 days at Christie's workshop last week. It seems that mass was not greatly increased due to higher quality of metals used in the construction. I think that many changes happened in this category. Of course, we cannot be sure until we weigh it.
Taber: Of course, don't guess. We will not gain anything by assuming things, especially since the tank will be ready so soon.

Disadvantages of the T1 tank compared to the Christie tank

Wright: Colonel, you talked about three or four major deficiencies of the T1E1 and T1E2, which, in your opinion, cannot be corrected?
Colonel Cooper: Yes, sir.
Wright: Are these deficiencies corrected in Christie's tanks?
Colonel Cooper: Completely, sir! The engine is in the rear. In other words, the tank is protected from the smoke and dust that the engine produces when working. The driver sits in the front, and can see perfectly what is happening in front of the tank.
Wright: He does not sit on top of the engine?
Colonel Cooper: The engine is in the rear. It is separated from the crew compartment. As a result, it is not hot, or at least as cool as possible in a closed metal box. the third deficiency I mentioned was the awful jumping of the gun, making it impossible for the driver to aim. The gun constantly moved up and down, as the tank did. The Christie tank gracefully handles bumps and inclines, and the gunner can follow the gun sight.
Wright: As I understand, Colonel, it is very difficult to safeguard the crew in modern tanks or the T1E1 and T1E2 tanks.
Colonel Cooper: Are you talking about T1E1 and T1E2 tanks?
Wright: As you said, it is difficult for the gunner to service the gun.
Colonel Cooper: Captain Cullen, an instructor at the tank school, has one of the largest black eyes I have ever seen, delivered by his tank's gun sight.
Wright: I think it would be very unpleasant to be shaken up so much that you hit the ceiling.
Colonel Cooper: Captain Tarp suffered from this. He hit his head on the ceiling.
Wright: As I remember, there was a claim made to the commission that when installing a turret, or in other words, making the tank complete, we must make the tank 1.5-2 feet longer to make room for the gunner and driver, and thus increase its weight. Is that correct?
Colonel Cooper: No, sir. I don't think that this would add half an inch to the tank's length.
Taber: When the tank arrives, you can make your own conclusions regarding its mechanical reliability.
Colonel Cooper: Yes, sir.
Taber: What about speed and lightness of controls?
Colonel Cooper: I can give you an answer if I knew if you wished to investigate a tank of this size, or a smaller or larger tank.
Taber: You will have the opportunity to test types of tanks with the initial chassis that, possibly, will be unsatisfactory.
Colonel Cooper: Initially, the chassis was the product of an extremely poor man. Despite doing things to it that we should not have done, it held out. We wanted to answer a series of questions with government vehicles, but we would not hesitate to explore them on Mr. Christie's vehicle, since we didn't want to break his only tank.
Barbour: Colonel Cooper, we are thankful for this information.

Major Brett's Testimony

Barbour: What do you think about this Christie tank?
Major Brett: I think that the Christie tank is a more attractive vehicle than any currently in use by any armed forces.
Barbour: Compare it to modern tanks we possess.
Major Brett: We only possess one tank, Mr. Barbour.
Barbour: T1E1?
Major Brett: No, sir, I did not mean that tank.
Barbour: I meant the types of tanks that we possess.
Major Brett: We possess several types of Christie tanks, different from the T1E1.
Barbour: How valuable are Christie tanks, compared to other types of tanks, for tank operations, as in all the goals which a tank is meant to accomplish.
Major Brett: There can be no comparison. I do not wish to mislead you, but the Christie chassis can be used in several tanks with different sizes and weights, as well as on trucks, self propelled gun mounts, and many other tasks. For example, the currently developed tanks are of the 4-wheeled suspension type. There are no reasons why they cannot be converted to 3-wheel suspension types, resulting in a light tank, despite us not endorsing that term. This can radically reduce mass, and give us a smaller tank, or increase it, and give us a larger tank.
Barbour: Is there some kind of limit to a tank's size?
Major Brett: There is a tactical limit.
Barbour: What does that mean?
Major Brett: Tactics suggest that a tank of this type should not surpass 20 tons.
Barbour: From your observations of the trials, can you make the conclusion that the ministry needs to acquire a number of these tanks, set them as the standard tank of the army, or do more trials need to be performed before accepting them?
Major Brett: It is difficult to answer this question, Mr. Barbour. The Christie chassis currently satisfies the requirements of the tank forces. We know that any mechanism has defects, and we must be ready for them. There is no such thing as a perfect machine, no matter how much you pay for it. Currently, it is not as important for the tank forces to move forward mechanically and build new tanks for the future, as it is to develop tactical requirements. The most important requirement is speed. No tank of the tractor type, developed until now, could match our speed requirement, either on a strategic or tactical scale.
Barbour: What is the performance of Christie tanks compared to tanks of other armies?
Major Brett: Christie's tank is the only one in the world with strategic mobility. No other tank in the world has been made with it in mind. The strategic mobility of other tanks depends on trucks, which deliver them to the battlefield.
Barbour: Was this strategic mobility proven?
Major Brett: Yes, sir. Tactically, the speed of this tank surpasses all other tanks. The fastest tank I have seen was the Vickers tank, which reached 46 kph.
Barbour: Do you have the latest Christie tank for trials?
Major Brett: No, sir, we do not have the latest Christie tank.
Barbour: Does the tank you tested at camp Meade provide enough information for you to decide if it is worth buying?
Major Brett: Yes, sir. Considering the principles of the tank forces, doing so is in the interests of national defense. However, we did not make any conclusions tactically. We think, or at least I think, that we will solve very important issues and will be able to explore tactical issues of national defense, if we accept the Christie tank as it is.
Barbour: You think that it has been through enough trials?
Major Brett: Obviously, we will continue tactical and mechanical trials. The issue of a complete tank does not interest us, as the Tank Corps can develop our own hull. We wanted to consult on the layout of the fighting compartment, what type of tank is needed, where the driver would go, etc. However, while we are interested in one specific vehicle, especially since the vehicle does not even have a fixed weight, and is not finished due to its lack of turret, we cannot make an evaluation of its power. At this horsepower, adding two tons is pretty simple. When the issue of rejecting a tank because it has no turret arises, we do not very much care about those details.
Barbour: Is it possible to drive a Christie tank at maximum speed with the driver inside?
Major Brett: Yes, sir.
Barbour: And the driver will look through an observation port?
Major Brett: He uses the sight and the observation port. During shooting, he uses the sight. During driving, he uses the observation port.
That is also an important issue, Mr. Barbour. We have several types of vision devices on the tank. One is a port that is a narrow slit in the tank's armour, which does not allow bullets to pass through. It is only 3/10 of an inch in size. There are several of these slits, which can be covered up. Of course, if the tank is not under fire, there is no need for this precaution, but it is necessary to keep them closed when the tank is in danger. You can keep it open at 7/10 when the tank is not on enemy territory and not under fire.
Barbour: Do you have any statements on the Christie tank that you would like to share with the commission?
Major Brett: I would like to point out one thing. I am very interested in receiving the best tank for national defense. I think that the Christie tank, the one that carries within itself its method of delivery (the wheel drive), and then, on its own power, provides tactical mobility with its tracks, is the most economical, not only financially, but tactically. It is very difficult for a commander of a tank regiment to manage 223 tanks, as well as the trucks necessary to transport them, especially when he has to hold against an attack from the ground or air. This would demoralize the regiment. With wheeled tanks, there is less of a threat from a ground or air attack, as we would possess equal chances. Bombs pose no danger to a tank, outside of a direct impact, but are dangerous to trucks, as they can damage unprotected components with shrapnel. The most important thing about the Christie tank is that it provides flexibility to the commander, strategic power, and strategic mobility.

Advantages of the Christie tank

Barbour: Are you familiar with the Christie tank?
Captain Tarp (head of the experimental tank department): Yes, sir, with every aspect of it.
Barbour: Please tell the commission everything you know about this tank.
Captain Tarp: When the tank arrived at Fort Meier, the officers familiar with tanks immediately saw that this was an interesting and promising vehicle. As it was, there were parts of the tank in its current state I did not like, namely that it did not have armament, the gears switched so fast, it was hard for the tank to move slowly, and it had old tracks that traveled 2000 miles on the old McFadden tank several years ago. We also tested it, but that's a thing of the past.
Barbour: Did you test it at Fort Meade?
Captain Tarp: Yes, sir. It weighed 5.5 tons. Some people think that it would be worthless if it weighed more. When we sent it back, its mass grew three tons. But it was an overall gain, and the tank became easier to control, and travel became smoother. While the tank was there...
Barbour: At Fort Meade?
Captain Tarp: No, at Christie's workshop. We got a new gearbox, and could control the tank as well at low speeds as at high speeds. Since the tank needs to be able to move slowly to avoid craters and trenches, this was a big improvement. During the trials, several weaknesses were discovered, and easily corrected. The new tank that he is building had some things that we did not like. We asked him to change them, and he did, at his own cost.
Barbour: in the new tank?
Captain Tarp: Yes, sir. In the new tank, we wanted to driver to be placed in the front of the tank, where he could see the ground when descending into a crater or a trench, and he put the driver in the front. In the current tank, the gunner is placed to the rear. He should be in the center, where it shakes less. When the gunner is in the rear or the front, he shakes too much when the tank moves through harsh terrain. We try to avoid this. We also want the gunner to be protected.
Barbour: The same way it happens on a ship?
Captain Tarp: Yes, sir. The center of the ship is the calmest spot. The same is true of a tank. It is hard to aim with a gunner that sits in the rear of the tank, like on the T1E1 and T1E2. The gunner cannot shoot accurately in this position, and we do not want him there.
Barbour: Have you seen the tank that Mr. Christie is working on right now?
Captain Tarp: Yes, sir.
Barbour: What do you think of it?
Captain Tarp: I think that this is the best vehicle that has been developed in the area of tanks. It is ten years ahead of its time, and, I must say, Mr. Christie is always 10 years ahead of his time. He invented front drive wheels for a car, which are only now being implemented in practice.
Barbour: He invented that 10 years ago?
Captain Tarp: Yes, even more, close to 20 years ago. He is very creative, and full of new ideas. I don't think there are any barriers in the field of mechanics that he did not overcome.
Barbour: When did you see the latest tank?
Captain Tarp: In the end of November.
Barbour: When will it be ready for trials?
Captain Tarp: It will be ready by the start of next year (1931).
Barbour: When will you start trials?
Captain Tarp: Mr. Christie was going to bring the vehicle to Fort Meade and Washington before taking it to official trials at Aberdeen.
Barbour: Will the official trials be done by the supply commission?
Captain Tarp: It will be a joint commission.
Barbour: A joint commission made of tank officers and what others?
Captain Tarp: Cavalry and several other officers.
Barbour: Can this joint commission judge the adequacy of a tank?
Captain Tarp: No, sir. The commission just makes a report and recommendations.
Barbour: What do you do when there is a difference of opinions?
Captain Tarp: I don't know, sir.
Barbour: Allow me to put it this way. If there are different opinions between different branches, say, the tank officers think that the tank is a step forward, but the logisticsofficers do not agree. Cavalry agrees with the tank officers, and other officers do not consider the tank interesting. What happens in that case?
Captain Tarp: I don't know, sir. Usually the tank speaks for itself.
Barbour: Yes, you are right. The people that will have to service these vehicles and work inside them will always be able to talk about them.
Captain Tarp: Yes, sir. We know what kind of tank we need, but other people try to tell us what tank they think we need. Years of experience prove them wrong.
Barbour: that is not a practical method.
Captain Tarp: No, sir. I can read you a list of 15 complaints and show how they can be avoided, if you so choose. I have it with me. They are in the order that they were presented to the Christie tank, and none of them apply to it.
Barbour: Is it brief?
Captain Tarp: Yes, sir.
Barbour: Can you summarize each point in one or two phrases?
Captain Tarp: I think so, sir. One of the comments was that the vehicle was not good, since Christie's previous vehicles did not perform well. It is necessary to say that out of all vehicles bought from Christie for $839,000, only one was a tank, worth $89,000. All other vehicles were meant for towing guns.
The bad performance of the gun tractors absolutely does not apply to Christie's new tank.
"Tests performed in 1929 were very insufficiently exhaustive". The tank was tested for 14 months at Fort Meade. The tests cost $32,000, and Mr. Christie footed the bill. 14 months was enough time to explore the tank's construction. We are not too worried about what is on top. We are studying the suspension system, what we can expect from it, how well it performs.
Barbour: Would you build tanks based on this prototype?
Captain Tarp: Yes, sir. The department of logistics can put anything they want on top. We have our suspension system, this is exactly what we want.
"The vehicle being tested at Fort Meade is very different than the vehicle submitted by Mr. Christie for satisfying the requirements." That is true. That vehicle had characteristics we were unhappy with. We demanded that Mr. Christie make some changes, and he did. Some of the changes are listed here.
Barbour: After the changes, were the characteristics satisfactory?
Captain Tarp: Yes, sir. The new prototype was changed, and is even better.
Taber: The next prototype will probably change again.
Captain Tarp: Yes, sir. That is very likely. Currently, the system is good, as far as I can tell from the latest observations. I studied it very carefully.
"The requested price is too high."
The initial price was set at $35,000 per tank. When the department of logistics wanted to buy them, Christie asked for $40,000. As you can see, the price is not too unreasonable, especially since the $35,000 included blueprints, which would cost large amounts of money, and the right to manufacture our own tanks. OF course, this is a different matter. I will not fixate on it.
"The society of automotive engineers at the logistics committee gave a negative opinion of the proposed project".
When I was there last November, Mr. Majorie, the senior engineer from Mac, was also there. I invited him to take a ride on the tank for the first time. He was impressed by the mobility, lightness and ease of the controls, as well as the technical construction of the tank, and gave the highest praise for it.
"The proposed project has many crippling defects".
Some of the listed defects are "the tires are overloaded, like on a wheeled truck". This is incorrect. Each tire holds 1200 pounds of load, and the limit is about 2000 pounds.
Barbour: Are these sturdy rubber tires?
Captain Tarp: Yes, sir, very sturdy rubber tires.
"There is no track freeing mechanism".
This means that when some object gets between the tracks and wheels, the track stops. The Christie tank does not have a mechanism to free its tracks like other tanks do, but it has a similar mechanism. I could explain it to you in a technical manner. The wheels are suspended on springs, and they can rise and lower. When the track tightens, it attempts to bring all wheels up, and frees the object. Tests proved that this is a satisfactory method.
Here is the list of defects. Would you like me to stop here?
Barbour: Complaints against the tank?
Captain Tarp: No, sir, mechanical defects found by the department of logistics.
Barbour: How many are there?
Captain Tarp: 12-15.
Barbour: Tell me of the most notable ones.
"Lack of a differential when in wheeled mode"
Captain Tarp: The subject is the differential on the rear of a car, so one wheel can move slower than the other. Tests showed that this is unnecessary. A lack of a differential did not lead to any complications. All it does is slip, and we have determined that without it, there are no ill effects on the chassis.
"Mechanical joints where metal touches metal at high speeds".
They performed well during tests, and were not damaged.
"Lack of a regulator for attacking rear chains".
There is a regulator for gear chains. We would not use chains at all. We are against them, and recommend against it in future tanks that move with toothed wheels, like tractors, since a chain leads to a series of complications and gets in the way.
"The gearbox with sliding gears makes it difficult to switch gears at any speed and can lead to a failure to engage the gears".
This never happened during trials.
"A lack of a graphite rod or any other item for servicing auxiliary components of the engine or gearbox".
Mr. Christie invented a new system for servicing those parts, which is very satisfactory, and never caused us problems.
"Lack of an air filter for the engine".
Irrelevant. You can put on an air filter, if you want.
"Inaccessible engine".
The inaccessible engine isn't that important. It is important for us to know if we can exchange components, and how long that takes. It is not important if you can screw off the nut on the bottom of the engine. That is meaningless. We need to know if the engine can be removed, how fast the new gearbox can be installed, how quickly the tank can be ready for battle.
"The ground pressure of 10.5 psi is too great. It needs to be less than 7 psi".
This is incorrect. Data shows ground pressure to be 7-8 psi.
"There is no rear steering mechanism in wheeled mode, which is dangerous".
This is correct.
"There are no brakes".
This is incorrect. There are brakes, and always have been.
"The wheels are very poorly attached to the cantilever for a suspension with mobile tracks".
If this is true, there needs to be more evidence. Everything was fine in tests.
"The center of mass is too far back".
The center of mass coincides with the center of the tank, and is located where necessary.
"The blueprints are incomplete, contradicting, and unclear".
Mr. Christie did not show detailed blueprints to that commission.
"The tank only has a crew of two"
Taber: Did he show you detailed blueprints?
Captain Tarp: Yes, sir. In the future, we hope to construct a fighting compartment for three crewmen. We can do that later.
"The tank can only mount a 37 mm gun".
This tank can also have a 75 mm gun, if you so wish.
"The chassis weighs as much as a medium tank, but performs like a light tank".
This is incorrect. We do not build light, medium, or heavy tanks. We build tanks that solve specific problems.
"The tank has no well-defined role".
We can make a lighter tank with a specific role, but this tank also has a role, and heavy tanks also have their roles.
This tank is needed for fast breakthroughs of the enemy lines or fast flanking maneuvers, neither of which can be done with other tanks. Tanks meant to attack the enemy front lines are built differently. Armour on those tanks needs to be an inch or an inch and a half thick, so it can withstand anything the enemy can throw at it. For a tank of this type, that is not needed. It needs to be protected from .30 caliber. A heavy tank can go deal with anti-tank defenses. After that, we will send fast tanks to the breach, which will thrive in the area devoid of anti-tank defenses. This is only one way to use these tanks, of course.
"The crew compartment is unventilated".
The crew compartment is ventilated very well. The engine takes in air from the crew compartment. Additionally, I must add that, while impossible for the T1E1 and T1E2, we could protect this tank from gases in its current form. The engine and crew compartments need to be separated. If we can protect the crew compartment from external air, when we can use oxygen tanks to enable the tank to cross infected areas. With a tank that has the engine in the front, with the gunner and driver in the back, it is not possible to be protected from chemicals, and we must achieve this protection in tanks of other types.
"The hatches are unsatisfactory, and very dangerous if the tank catches fire or flips over".
We corrected this in our Christie project. Mr. Christie did not take this into account. He did not think that these things could happen, it is out of his scope. It is in ours, and we dealt with it.
"The tank is too heavy to be used in a mechanized division".
I have here a claim that the tank weighs about 30,000 pounds. This is 15 tons. The tank does not weigh that much. The last time I weighed it, the chassis weighed 8.6 tons. When we put on a turret, gun, ammunition, it will weigh about 11 tons.
"The two-man crew has to separate the track into three or four parts to remove it and continue on wheels".
This operation took 17 minutes when performed by 2 people at the test.
Additionally, 4 of these 15 defects in the Christie tank are present in the T1E1."