Fiat 1100 Roselli Aerodinamica

The Colli Fiat 1100 Rosselli Aerodinamica was a one-off competition sports car constructed in 1939 for participation in long-distance road racing during the final prewar season. The car was built by the Colli workshop using Fiat 1100 mechanical components and a lightweight tubular chassis supplied by Gilco, reflecting a production context characterized by small-scale specialist constructors operating outside factory programs. The project emphasized experimental aerodynamic solutions applied to a modest-displacement production-based platform, consistent with contemporary Italian approaches to efficiency-driven competition design. The mechanical foundation consisted of a Fiat 1100 inline four-cylinder engine adapted for sporting use. Period documentation indicates the adoption of a hemispherical cylinder head configuration, representing a significant technical modification intended to improve volumetric efficiency and combustion characteristics. The engine retained its front-mounted layout driving the rear wheels, with the emphasis placed on reduced frontal area and body-induced drag rather than on high-output engine development. The drivetrain and running gear were configured to meet endurance competition requirements, aligning with the regulatory framework governing sports cars in events such as the Mille Miglia. The bodywork, attributed to Rosselli, was executed in lightweight materials and embodied an advanced aerodynamic philosophy for its time. The design featured enveloping, fully integrated fenders, a low and rounded nose section, and a continuous body surface flowing toward the tail, with the open cockpit recessed into the overall form. This configuration minimized airflow separation and turbulence around exposed mechanical elements, drawing on prewar experimental research into streamlining that had begun to influence Italian competition cars in the late 1930s. The car is documented as having been driven by Enrico Beltrachini, who entered it in the 1940 edition of the Mille Miglia.