By the beginning of 1915 the Western Front was in deadlock with neither side able to penetrate the hail of machine-gun fire or cross the enemy trenches. The answer to the problem was to produce a Land Battleship, similar to the armoured cars used successfully by the Royal Naval Air Services (RNAS) during the early period of the war, when the front was still fluid, but capable of crossing the muddy shell pounded ground and the enemy defences of the static front. To coordinate operations, the Landship Committee was formed and their recommendations were that an armoured vehicle firing a high explosive shell should be produced capable of crossing a standard German trench of eight foot gap, and four foot mound. Various designs were tried ranging from vehicles that "walked" to gigantic powered wheels, but none were really successful, or strategically satisfactory.
Instructions to Mr William Tritton of William Foster and Co Ltd of Lincoln, England, assisted by Lieutenant W G Wilson of the RNAS, to design a small landship with so called Bullock tracks were given when these other landship projects, and parallel experiments, seemed unlikely to lead to a successful conclusion in time to play a useful part in the war. In America agricultural tractors with caterpillar tracks were receiving wide acclaim and the Landship Committee eventually purchased two "Creeping Grip" tractors from the Bullock Tractor Co. of Chicago, USA. The Chairman of the Landship Committee (Mr E Tennyson d’Eyncourt) gave the order for the experimental vehicle on 29 July 1915. Work on what was known at first as the "Tritton Machine" was commenced immediately. The Tritton Machine was, in essence, like one half of the articulated gun-equipped landship with Bullock tracks, designs for which had already been drawn up by Colonel Crompton. The hull was a rectangular armoured box (boiler plate was, in fact, used) carried on tracks of shorter length than the body and surmounted by a turret. The armament was to be a QF 2-pdr gun and several machine-guns.
The "Creeping Grip" tracks ordered specially from the Bullock Tractor Co were longer than the normal type used on the agricultural tractors tried out in earlier landship experiments. They were supplied as a unit complete with track frames and wheels and had seven small road wheels and five guide wheels compared with the four road wheels and three guides of the standard type. No attempt was made to introduce the Rolls-Royce engines on shortened car chassis, some of which had already been completed for the twelve Pedrail landships: this would have complicated the design and a 105hp Daimler six-cylinder engine, gear-box and differential of the type well known to Tritton from use in Foster's Wheeled tractors, was used to power the Tritton Machine, or "Lincoln Machine Number 1" as it was also known. Transmission was to the centre of the track frames, which were pivoted, and thence by chain drive to the track sprockets at the rear.
There was little data on full tracked vehicles to go on; most of the tracked agricultural tractors of the period, including the Bullock tractors were, in modern terms, "half-tracks" with the front end supported on wheels. Tritton made provision for a pair of wheels steerable on the Ackermann principle, at the rear of the machine. These wheels were intended to improve the balance, assist in crossing trenches and aid the normal steering of the vehicle, which was by braking on either track.
The Tritton Machine was the first vehicle to be designed and completed as a landship, or tank, but was not entirely successful because the lengthened Bullock tracks were found to be of poor quality and were still too short and a trench of only 4-foot width could be crossed, when the current War Office requirement was for a 5-foot trench.
These shortcomings were foreseen and a second type was drawn up by Tritton, assisted by Wilson, even before the first was completed. This had improved tracks, specially designed, and new track frames (about 3 ft longer) and running gear, although the other features remained the same. This became "Little Willie" - the name is said to be a reference to the German Kaiser. Little Willie was about 26 feet long by 9 feet high, and weighed about 14 tons. Trackplates were 20.5 inches wide steel plates riveted to guided links. The 105hp engine was retained. Steering was achieved by applying brakes or clutch to one track, with minor course corrections made using rear tail wheels. The round plate on the superstructure blanked out the turret ring, which was to support a 2pdr gun giving a 360° traverse. A gun (probably a fake) had been fitted to the Lincoln Machine Number 1, but it had been covered during trials.
The modified Lincoln Machine Number 1, or "Little Willie" as it then become known, started testing early in December 1915, and was much better than in its previous form but was still unable to meet new War Office obstacle-crossing requirements. In addition to this it was found to be top heavy and the proposed 2 pdr gun was not capable of delivering an HE shell. A revised design known as "Big Willie" or "Mother", despite its new outward appearance was mechanically almost identical to its predecessor, the main difference being that the track was passed over the superstructure giving greater trench-crossing capacity and stability. Two sponsons were added which, although giving a restricted traverse, could deliver HE shells from the 6-pdr guns. This became the first operational tank, the Mark I. Also, this design provided the basis for British tanks up to the Mark VIII ("The International") in 1919.
The fantastic thing is, that this vehicle is still in existence, and can be seen in the Tank Museum at Bovington, England. Most of the interior and the motor etc are gone, so it is basically an empty hull. A close examination of these photos will reveal redundant bolt or rivet holes associated with the earlier equipment. These photos have been taken by Knut Erik Hagen and P Radley, and are used here with their permission.
There is another walkaround of Little Willie at the AMMS Brisbane website.
The embedded video contains a description of Little Willie and its design features narrated by David Fletcher, Curator of the Bovington Tank Museum.
If you want to model "Little Willie", there is a rather nice 1/76 scale kit by Matador Models.
B.T. White. 1970. Tanks and and other Armored Fighting Vehicles 1900-1918. Blandford Press, London, England.