Another theme I've found intriguing are the three wheeled armoured armoured vehicles (sort of Reliant Regal meets Land Ironclad). Here are details of a few
The three wheel configuration was considered for a number of armoured vehicles. The three wheeled Ivel Tractor first introduced in 1902 at Biggleswade in the UK lays claim to be the first ever commercial internal combustion engined agricultural tractor. The original was still running in 2005. The Ivel proved to be one of the more successful early agricultural tractors and spawned a number of copies. In 1903 an armoured version for military use was produced in prototype form. It was completely armoured but unarmed and appears to have been intended to act as a form of battlefield casualty recovery vehicle. There is certainly a blurry photograph of the prototype with what seems to be a red cross marking on its side.
Quite how it was supposed to operate is unclear; there was certainly no room in the cab for a stretcher. It is possible that an armoured trailer would have been used. The whole of the rear of the cab could be swung out to form an additional shield on one side. This may have been intended to provide cover for stretcher bearers. This would however have exposed the fuel tank, positioned beside the driver, to any fire from the rear (and probably the driver himself as well). The tractor was doubtless expected to be able to trundle up and down the battlefield with bullets pinging off it much like one of the armoured tractors used on modern golf driving ranges. It would have been a sitting duck for any artillery or infantry armed with demolition charges.. Openings for the crew (apart from the door) appear to have been limited to one forward facing slot for the driver (it was a one man vehicle), there was no way to see to the side or rearwards. Vision would have been extremely limited and any wounded would probably be in danger of being run over by the vehicle meant to rescue them. The Ivel Armoured Tractor remained an interesting prototype.
When seeking solutions to the need for armoured vehicles capable of operating in the broken and shell crater pocked ground of First World War battlefields some designers did not turn to the used of tracked vehicles (such as those that led to the tank) but instead looked at the concept of the ‘big wheel’. The idea was that by using wheels that were both very wide and of large diameter the ground pressure could be kept lower whilst at the same time allowing trenches and other holes in the ground to be bridged. The successful use in rear areas of very powerful tractors with relatively big wheels led some credence to the concept. One such vehicle was developed in 1916 at the request of the German Ministry of War, this was the eighteen ton Treffas-Wagen battlewagon which was trialled in February and March of 1917. It was a giant armoured tricycle with a pair of very broad 11 foot diameter wheels at the front and a wide roller at the rear. Steering was achieved by swivelling the roller and the turning circle must have been extremely wide. The use of such wide wheels would improve ground crossing and provide a means of flattening barbed wire. Armament was a single 20mm automatic cannon protruding from between the front wheels; this weapon would have had a very limited traverse. The crews’ view would have been very restricted as the wheels blocked any possible vision except directly forwards. The driver would be like a horse in blinkers. For the same reason it was impossible to mount any secondary armament to protect the sides and rear, this lack would have made the vehicle very vulnerable to infantry attack. Given the limited vision and the less than delicate steering manoeuvring such a monster on the battlefield would undoubtedly been difficult. It could well have been as much a menace to the infantry it was supporting as to the enemy (perhaps initiating the concept of ‘friendly squash’.
The German military were in any case still not particularly convinced of the value of tanks so that support and funds for their development were limited. The A7V tank was already under development and, despite its many shortcomings, offered a much better solution than the Treffas-Wagen. Consequently no further development of Germany’s big wheel solution was undertaken.
In 1918 an American attempt to develop a big wheel based solution resulted in the production of another armoured three wheeler. Produced by the Holt Tractor Corporation this vehicle could be described as being like a reversed Iver on steroids. Unlike the Iver it was armed. It appears to have been sometimes designated as a Holt tank even though it had no tracks (even though Holt track systems already formed the basis for contemporary tank designs in France, Germany and the USA). This may be the result of confusion with another Holt armoured vehicle (the Gas Electric Tank) that definitely did have tracks. The single wheel on the Holt three wheeler was at the rear and being very wide could be described as a roller. This was used for steering (rather as with the Treffas-Wagen). A rudimentary unditching skid was fitted to the rear of the roller (although it is difficult to see of what use it would have been). The wide metal tractor style front wheels were eight feet in diameter. A 75mm mountain howitzer was mounted in the front of the vehicle (very much like in many German World War Two assault guns). Light machine guns could be mounted to fire to either side.
What made this three wheeled armoured vehicle especially unusual was its mode of propulsion – it was powered by two separate steam engines each with its own kerosene (paraffin) heated boiler), one engine to each wheel. Why this arrangement was chosen is now unknown, it does not appear to have been used for differential steering (slowing down one wheel and speeding up the other to effect turns), but in any case it was clearly not a good choice as the vehicle is reported to have broken down during its first official trial run after only managing to roll a couple of hundred yards. From the experiences of British tanks in France it was probably already clear to the relevant American authorities that tracked solutions were already available and these were superior to big wheeled tricycles. The Holt ‘Steam Tank’ was not proceeded with.
The ultimate three wheeled fighting vehicle had already been built in Russia. This was nothing less than a truly gigantic armoured tricycle and represented the logical (or perhaps illogical) conclusion of the Big Wheel argument. The enormous wheels were intended to be able to bridge the widest trenches. Even more extreme versions of this design had been mooted. These included the introduction of massive stabilising gyros and a revised structure with just one enormous front wheel, effectively producing a titanic penny farthing bicycle (although no thought appears to have been given as to how this would be steered). Perhaps fortunately, there was no funding available to pursue such Wellsian schemes. Only the basic tricycle design, credited to a M.Lebdenko, was proceeded with. A similar big wheel design was rejected by the British Landship Committee after some very crude wooden mock ups of the wheels had been constructed. It is not clear if there was any connection between the two designs or merely the coincidence of two identical bad ideas occurring at the same time. Given the timing it is possible that the Russian design had been offered to Britain. Fortunately the Landship Committee rejected the idea of the big wheel in favour of tacked solutions leading to the first combat tank.