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.
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.
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.