Cleveland Cletrac Model H,Cleveland Cletrac Model H ? The first tracked tractor in history, the Cleveland Cletrac Model H, was designed and built in the USA in 1917. It was equipped with a 20 hp, four-cylinder internal combustion engine, powered by petroleum or paraffin. In Europe, the forefather of tracked tractors was the English Blackstone Track Tractor, marketed starting in 1919. It had a three-cylinder, paraffin- or kerosene-fueled engine that developed approximately 25 hp. The first Italian tracked tractor was the Fiat 700 C, produced in 1932. It had a 30 hp petrol engine and was quite successful, thanks in part to the interest of the army, which had identified the new tractor as a valid alternative for moving mountain artillery, instead of mules. A smaller version (the Fiat 708 C, with an engine of only 20 hp) was used in the military campaigns in Somalia and Libya. In 1939, in the midst of the autarchic era, a historic tracked tractor appeared: the Fiat model "40," also known as the "Boghetto" after the engine designer, Professor Fortunato Boghetto from Valdobbiadene (TV). Its main feature, which made it a cutting-edge vehicle for its time (and even today...), was that the 40 HP engine was a multi-fuel engine, meaning it could burn any flammable fuel available: alcohol, gasoline, naphtha, diesel fuel, paraffin, palm oil, castor oil, animal oil, etc. In effect, it was a low-compression Otto cycle engine, with a cylindrical combustion chamber with a biconical opening arranged eccentrically and inclined with respect to the cylinder axis, almost simulating a Venturi tube. The fuel system was completed by an injector and a spark plug. With this configuration, the engine always operated with full air intake, and the fuel was metered so that, near the spark plug, the mixture was always rich enough to allow ignition. This ensured smooth engine operation and low fuel consumption. After the war, with the spread of diesel engines, the Boghetto engine was, as they say, "retired." The golden age of Italian tracked tractors began, their spread significantly favored by the topography of Italian agricultural land, which is classified as 35% mountainous, 43% hilly, and 22% plain, often with clayey and tenacious soils. Moreover, a typically Italian practice, at least until the late 1970s, was plowing to a depth of 50-60 cm. The wheeled tractors of the time were not yet as large and stable on slopes as their tracked counterparts; This led to the widespread diffusion of these machines in our countryside, so much so that, to meet farmers' demand, between 1930 and 1970, over 30 manufacturers were active in Italy, with more than one hundred models of tracked vehicles adaptable to any production situation. Today's reality Nowadays, the number of domestic manufacturers of tracked tractors has greatly decreased, but the demand for these machines has never stopped: in fact, a full 9% of new registrations in 2019 were classic tracked tractors (i.e., with steel pads), making Italy one of the countries in the world with the highest use of these vehicles. From a technical standpoint, thanks to their large ground contact surface and high power-to-weight ratio, classic tracked tractors are capable of developing excellent grip and therefore high tractive force. Furthermore, they provide good ground buoyancy (with an average ground pressure of only 0.25-0.50 kg/cm2), thus limiting compaction. They also offer excellent lateral stability thanks to their low center of gravity, smaller footprint compared to a similarly powered wheeled tractor, and a tight turning radius (in fact, they can pivot on the inner track). Disadvantages include their lower ergonomics compared to wheeled models (although this aspect has been significantly improved in recent years), their limited suitability for certain operations (e.g., haymaking, crop maintenance, transport), their slow speed, and the need to attach special overshoes to the skids when traveling on public roads. The maximum speed permitted by the Highway Code is only 15 km/h. Consequently, these machines are by their very nature not very multifunctional; However, they prove to be a godsend when high tractive force and excellent stability are required, especially on slopes and heavy terrain. Current classic tracked tractors feature impressive construction features, albeit to a lesser extent than wheeled models, that achieve a high level of technical performance.