An Alternative Take on Bristish Cruiser Tanks:
In October 1928, Christie’s M1928 was demonstrated at Fort Myer, Virginia. There the Army's Chief of Staff, General Charles P. Summerall, and other high-ranking officers were impressed, however, the Tank Board was less enthusiastic. They noted that the vehicle's armour was very thin and could not survive penetration by the smallest armour-piercing antitank rifle or artillery piece. The Board also differed with Christie on its guidelines for tank capabilities, which were based on a radically different theory of armoured warfare than that used by Christie. For the Infantry Tank Board, armour and firepower were more important design criteria than mobility, and the M1928 prototype was passed to the Cavalry for further evaluation. The Cavalry's thinking at that time was based on armoured cars, and it wanted to develop the M1928 as an armoured car chassis. Once again, Christie's concept of how his vehicles should be used, together with his difficult nature, resulted in disputes with Army officials. Ultimately, the Secretary of War rejected mass production of the M1928, citing excessive acquisition costs.
Christie then, somewhat foolishly, felt he was justified in selling his inventions to the highest bidder. A long and complex series of exchanges between Christie and foreign governments 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.
Initially, in early 1930, Christie promised to sell his M1928 tank design to the Polish government, but the deal fell through and, to avoid potential litigation, he eventually returned the payment made by the Polish government, which never obtained the tank they had ordered.
Although the USSR did not have diplomatic relations with the USA at the time, and was prohibited 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 March 1930 using a series of deceptions. On 28 April 1930, Christie's company agreed to sell AMTORG two Christie-designed tanks, documented falsely as agricultural farm tractors, and without prior approval of the U.S. Army or Department of State. They were successfully shipped to the USSR where the Soviets used them to develop the BT series of tanks, forerunners of the massively produced T-34 tank of World War II.
Needless to say, the US Government, and the Department of State in particular, were not amused and Mr Christie was promptly arrested by the FBI and imprisoned on dubious charges of failing to gain export licences and tax fraud rather than aiding and abetting potentially hostile governments.
After favourable reports on observation of Soviet tank activities in 1936, the British War Office tentatively approached the US Government regarding the possible purchase of a license of the Christie design. Not unsurprisingly, the request was politely but firmly turned down.
Meanwhile, across the Pond in Britain, Sidney Horstmann had been developing suspension designs from the 1920s and through his Slow Motion Suspension Company had by 1930 produced a new design using two road wheels on a single bogie, each connected to a bell crank with a horizontal coil spring between the crank arms, and double-acting shock absorbers to control recoil. In 1934, John Carden of Vickers-Armstrongs had a "bright idea" for a new type of tank suspension and partnered with Horstmann's Slow Motion to turn it into a working design. Unfortunately, Carden was killed in an air crash in December 1935, but by this time he had designed a lighter tank platform that had been taken up as the A9, although later known as the Cruiser Mk I. In this version, one large wheel was fitted on one bell crank, and two smaller wheels to a shared arm on the second crank. This went into production in 1937 as an interim type until the Army could develop something better. The same suspension was then used on the larger A10 Cruiser Mk II which came to its ultimate form as the Valentine tank.
At much the same time in the US, Harry Knox an engineer for Rock Island Arsenal, was developing a similar two-wheeled bogey suspension unit but with an innovative double vertical volute spring in place of Horstmann’s coil spring. The suspension was developed in 1933 and was first tested on a T2E1 light tank prototype in 1934. The Rock Island Arsenal would go on to produce the M1 Combat Car, which entered service with the US Army in 1937.
Horstmann and Knox were fully aware of each other’s work, and it didn’t take long for Horstmann to convince the UK Government to approach the US Government for licencing rights to the more efficient volute spring suspension design. Easier to produce and easier to maintain and replace in the field than Christie’s design, the VVSS seemed like an idea solution to the UK’s future cruiser tank designs. Fortunately, the US Government were more favourable in their response to this request and the rest, as they say, is history…
Mk I Cruiser (A9) and Mk II Cruiser (A10) as OTL for completeness...
Mk III Cruiser (A13 Mk I) and Mk IVA Cruiser (A13 Mk II) with M1 Combat Car VVSS...
Mk V Cruiser A13 Mk III) Covenanter and Mk VI Cruiser (A15) Crusader I with M2 Medium VVSS...
Mk VI Cruiser (A15) Crusader III with M3 Lee/Grant VVSS...
Mk VIII Cruiser (A27M) Cromwell with M4 Sherman VVSS...
Cruiser (A34) Comet with M4A3E8 HVSS...
