 The first prototype development began in 1925. Produced in the Trubia Artillery Factory (Fábrica de Artillería Trubia), in Asturias, the tank was powered by a four-cylinder Hispano-Suiza 40 / 50 engine, the same engine the Spanish Army's military trucks had been equipped with since 1915. Given the Spanish Army's opinion that the FT was limited in firepower, the Trubia tank featured a special turret. The turret was designed in two articulated halves, which could traverse independently, each armed with a machine gun. Theoretically, if one of the machine guns jammed, the tank would still have another one to defend itself with. Furthermore, the vehicle's hull was provided with firing ports, to allow the crew to fire from within the tank. This prototype was put through a series of tests, and its success brought about the decision to continue development on a Spanish tank, leading to an improved Trubia tank design, known as the Modelo Trubia 75HP, tipo rápido, serie A (Model Trubia 75 hp, fast tank, series A).
