Wilson, Walter Gordon (1874–1957), engineer and inventor of the tank, was born 21 April 1874 at his family's home, Dunardagh, Temple Road, Blackrock, Co. Dublin, fifth son of George Orr Wilson, barrister, and Annie Wilson (née Shaw). Educated as a naval cadet at HMS Britannia, he studied mechanical engineering at King's College, Cambridge (1894–7), graduating with a first-class BA degree. His inventive genius emerged on meeting Percy Pilcher, a naval architect with an infectious enthusiasm for aeronautical gliding. In 1898, eager to explore the potential of mechanical flight, Wilson formed a business partnership with Pilcher and Lord Braye (who had introduced them), called Wilson & Pilcher, to develop an internal combustion aero-engine. He quickly designed a prototype but it was abandoned before completion in 1899 when Pilcher died in a gliding accident. Wilson was deeply affected by Pilcher's death and turned instead to motor-vehicle design. At a workshop in Westminster, London, he pioneered the Wilson-Pilcher motor car, with several viable design features including epicyclic gears, adapted later to both military and civilian use. He joined the motor manufacturer Armstrong Whitworth & Co. in 1904, for whom he designed one of a rapidly growing number of car models entering the market at the turn of the twentieth century. Moving to J. & E. Hall of Dartford in Kent (1908), he designed the Hallford lorry, deployed as a standard British vehicle of the first world war.
With the outbreak of war in August 1914, Wilson left Halls to join the Royal Navy, where he served as a lieutenant. Given his mechanical experience, however, he was assigned to defend Royal Naval Air Service airfields in France and Belgium using armoured vehicles, which he was also required to build. This opportunity resulted in his principal design achievement, the first generation of an armoured fighting vehicle (as yet untitled), which became a mobile, offensive weapon, inspired by existing armoured cars and the Holt caterpillar tractor. Wilson was engaged by the mysteriously titled ‘landships committee’, established February 1915 at the admiralty by the first lord, Winston Churchill, and headed by Eustace Tennyson d'Eyncourt, director of naval construction. Wilson worked under Lt.-col. Ernest Swinton, who conceived the idea of a multi-purpose armoured assault vehicle capable of withstanding enemy fire while safely traversing trenches and other obstacles, including barbed wire. Following Swinton's specifications of July 1915, he collaborated with William Ashbee Tritton, engineer and managing director of the contract firm William Foster & Co., Lincoln. Basing his design on their ‘Lincoln No. 1’ prototype of August–September 1915, Wilson top-mounted a coffin-shaped body of naval-style armour (for which he was guaranteed a supply of 6-pounder naval turret guns) and experimented with the Holt caterpillar track principle using an American-designed link plate called the Bullock. His completed working prototype was called the Tritton but given the nickname ‘Little Willie’ (commonly applied to the German crown prince). However, although it could climb obstacles, design problems remained, including a high centre of gravity (making it inclined to topple, even before adding a turret) and a track layout unsuited to crossing wide spaces and uneven ground in the shell-holed, trenched landscape of the Western Front. Yet Wilson and Tritton knew they had all the correct principles (adopted successfully in later tanks), if not the ideal proportions for local conditions.
To an anxious committee, Wilson introduced alternative sketches, prepared since September 1915, for a very different, lozenge-shaped or rhomboidal vehicle, not unlike a massive, elongated wheel, with tracks running around the whole body, from top to bottom. His alternative armament (replacing a top-mounted turret) was a pair of side-mounted, naval-style sponsons. The new design, initially named the Wilson but subsequently the Centipede, had the added aesthetic of menace, but was nicknamed ‘Big Willie’, somewhat offsetting its status as an instrument of terror. However, renamed Mother, predatory and monstrous, it excelled over Little Willie in trials and was passed for production in February 1916. Wilson transferred to the army in March and subsequently held the rank of major in the Heavy Branch (redesignated the Tank Corps, July 1917) of the Machine Gun Corps.
His legendary design, secretively labelled ‘tank’ before its deployment, shocked the Germans who first saw it at the Somme, 15 September 1916. Officially branded the Mark I, the machine in practice became easily bogged down, vulnerable to assault and capture. As it had never had comprehensive tests in the field. Wilson was urgently required to adapt it to battlefield conditions, including internal noise reduction and greater forward visibility. In spite of additional improvements (Mark VIII appeared in late 1918), British tanks retained Wilson's basic design until the war's end; the weapon's greatest single success was at Cambrai, November 1917. His epicyclic steering, which allowed the tank to turn, evolved to enable one driver rather than two to control the Mark V vehicle. It was acknowledged as the best heavy tank of the war.
Wilson was created CMG in 1917 and appointed chief of design at the mechanical warfare department until the war ended. In a note of irony, a number of tanks appeared on the streets of his native Dublin during the war of independence 1919–21. He himself remained in Britain after the war, invented the Wilson self-changing gearbox, and established his own firm, Self-Changing Gears Ltd, in Coventry. He was a member of the Institution of Civil Engineers and honorary member of the Institutions of Mechanical Engineers and Automobile Engineers, and of the Junior Institution of Engineers. Subsequent refinement in postwar tank models, including those with top-mounted turrets, continued until in 1937 Wilson introduced a faster mechanism to match the turning radius required of modern tanks. His recreations included fly-fishing, shooting, and other rural pursuits. He lived at The Elms, Itchen Abbas, near Winchester, where he died 30 June 1957.
Wilson married (1904) Ethel Crommelin (d. 1963), daughter of Samuel Octavius Gray of Swaines, Rudgwick, Sussex, chief accountant at the Bank of England; they had three sons.