The T4, T4E1 Medium Tank
The Christie M1931
John Walter Christie (May 6, 1865 – January 11, 1944) was an American engineer and inventor. He is best known for developing the Christie suspension system used in a number of World War II-era tank designs, most notably the Soviet BT and T-34 series, and the British Covenanter and Crusader Cruiser tanks, as well as the Comet heavy cruiser tank.
Early life and career
Born in River Edge, New Jersey on May 6, 1865, J. Walter Christie started working at the age of sixteen at the Delamater Iron Works while taking classes at the Cooper Union in New York City. He eventually became a consulting engineer for a number of steamship lines and in his spare time did some work on early submarine designs. Following the Spanish-American War he developed and patented an improved turret track for Naval artillery. At the same time he was also working on designs for a front-wheel-drive car, which he promoted and demonstrated by racing at various speedways in the US, and even competed in the Vanderbilt Cup and the French Grand Prix. In 1912 he began manufacturing a line of wheeled fire engine tractors which utilized his front-wheel-drive system, but due to lack of sales this venture failed.
In 1916, with the First World War waging in Europe, he developed a prototype four-wheeled gun carriage for the US Army Ordnance Board. But the Ordnance board had set out strict guidelines for weapons, and Christie refused to revise his designs to suit their requirements. Christie’s own personal stubbornness and his habit of offending those in the US Army and Ordnance bureaucracy would have ramifications for the rest of his career.
Later innovations and bureaucratic frustrations
Christie continued to submit designs to the Ordnance board, but none was deemed acceptable. A major reason was the poor cross-country performance, due to limited suspension capabilities. He therefore turned his attention to this problem, and after five years of development (at a cost of $382,000) he produced the revolutionary prototype tank chassis M1928 (Model 1928) design. He proudly referred to it as the “Model 1940″ because he considered it to be a dozen years ahead of its time. The M1928 still retained large road wheels with no return rollers for the tracks from his earlier designs, so that the tracks could be removed for road travel, allowing for greater speed and range. What made this prototype revolutionary was its new “helicoil” suspension system, whereby each wheel had its own spring loaded assembly. This reduced space in the interior of the tank, but (combined with a very light overall weight) allowed for unprecedented high-speed cross-country mobility, albeit at the cost of extremely thin armor. Another interesting feature of the M1928 and later Christie designs was sloped armor in front, which could better deflect projectiles fired against it. The sloped armor helped to compensate for its thinness. The Army purchased several of Christie’s tank prototypes for testing purposes and Christie’s patent, allowing them to produce prototypes based on his design.
In October 1928, the M1928 was demonstrated at Fort Myer, Virginia. There the Army’s Chief of Staff, General Charles P. Summerall, and other high ranking officers were highly impressed and strongly recommend that the Infantry Tank Board conduct further, official tests of the new vehicle. However, the Tank Board was less than impressed. They pointed out that the vehicle’s armor was very thin and could not survive penetration by the smallest armor-piercing antitank rifle or artillery piece. The Board also differed with Christie on guidelines for tank capabilities, which were based on a radically different theory of armored warfare than that adhered to by Christie. While Christie advocated the use of lightweight tanks with long range and high speed, designed to penetrate enemy lines and attack their infrastructure and logistics capabilities, they saw the tank as simply a supporting weapon to facilitate breakthroughs by the infantry, and help isolate and reduce enemy strongpoints near the front lines, much as they had been used in the previous world war. For the Infantry Tank Board, armor and firepower were far more important design criteria than mobility, and the M1928 prototype was passed to the Cavalry for further evaluation.
Unfortunately, however, the Cavalry’s thinking at that time was geared toward armored cars, and wanted to develop the M1928 as an armored car chassis. Once again, Christie’s concept of how his vehicles should be used, together with his difficult nature, resulted in clashes with Army officials. One member of the Cavalry Evaluation Board who appreciated both Christie’s design and tank warfare concepts, was Lt. Colonel George S. Patton. Patton, and his friend Major C.C. Benson, strongly supported adoption of the M1928 as the basis for a Cavalry tank.
Ultimately, the Secretary of War rejected mass production of the M1928, citing excessive acquisition costs. Embittered, Christie felt he was justified in selling his inventions to the highest bidder. He began looking to foreign governments to purchase his advanced chassis and suspension systems; Poland, the Soviet Union and Great Britain had all expressed interest in the designs. A long and complex series of exchanges between Christie and various foreign governments soon followed. These were technically illegal, since Christie never obtained approval of the US Department of State, Army Ordnance, or the Department of War to transfer his designs to potentially hostile governments.
Dealings with foreign governments
Initially, Christie promised to sell his M1928 tank design to the Polish government. In 1929, Captain Marian Rucinski of the Polish Military Institute of Engineering Research (WIBI) was sent to the USA, and soon learned of the M1928 tank being constructed by Christie’s company, the US Wheel Track Layer Corporation in Linden, New Jersey. Rucinski also learned of a design for an improved tank (later known as the Christie M1931) that had recently gone to blueprint. Rucinski’s opinion was so enthusiastic that on February 16, 1930 a special acquisition commission was dispatched to the United States, headed by the Chief of the Engineering Department, Colonel Tadeusz Kossakowski. The commission signed a contract with Christie in March for construction and delivery of a single M1928 tank, and paid a pre-payment to him. Christie later reversed course and failed to deliver on his contract obligations, and faced with potential litigation, eventually returned the payment made by the Polish government, which never obtained the tank they had ordered.
- Spanish Republican Forces destroyed Russian BT 5’s
Though the Soviet Union had no diplomatic relations with the United States at the time, and was barred from obtaining military equipment or weapons, Soviet OGPU agents at the trade front organization AMTORG managed to secure plans and specifications for the Christie M1928 tank chassis in 1930 using a series of deceptions. On April 28, 1930 Christie’s company, the U.S. Wheel Track Layer Corporation, agreed to sell Amtorg two M1931 Christie-designed tanks at a total cost of $60,000 dollars US, with the tanks to be delivered not later than four months from date of signing, together with spare parts to the purchased tanks for the sum of 4000 dollars. Rights were also transferred to the production, sale and use of tanks inside the borders of the U.S.S.R. for a period of ten years.. The two Christie tanks, falsely documented as agricultural farm tractors, were sold without prior approval of the U.S. Army or Department of State, and were shipped without turrets to the Soviet Union. Christie even concluded an oral agreement to provide personal technical support services to the U.S.S.R. The Soviets later improved upon the basic Christie tank design, adopting its sloping front armor for its BT tank series of infantry tanks. The BT itself was further refined into the famous Soviet T-34 tank of World War II, retaining the sloping front armor design, now adopted for side armor as well.