Alfa Romeo RL Sport Castagna

The Alfa Romeo RL Sport Castagna was a custom-bodied open tourer produced in 1923 on the RL Sport chassis by Carrozzeria Castagna of Milan. The RL series, introduced by Alfa Romeo in 1922, was developed under the direction of chief engineer Giuseppe Merosi and constituted the company’s first six-cylinder production model. The RL Sport, a high-performance variant, was intended for private sporting use and long-distance touring. The chassis employed a six-cylinder inline engine of 2,994 cc displacement. The unit was naturally aspirated, with a single carburetor, overhead valves, and side camshaft operation. Output varied slightly by specification, with the RL Sport delivering approximately 71 CV at 3,600 rpm. The engine was paired with a four-speed manual transmission. The chassis utilized a ladder-type steel frame with semi-elliptic leaf springs front and rear, and mechanical drum brakes on the rear axle only. Front-wheel braking was introduced later in the model’s development. The body was executed by Castagna, one of Italy’s leading coachbuilders of the interwar period. The design featured a long bonnet, flared wings integrated into the flowing side panels, and a dual-cowl layout. The construction was carried out in hand-formed steel and aluminum over a wooden subframe. The passenger compartment included separate seating for driver and passenger, with minimal instrumentation and a folding canvas roof. The visual composition reflected the transitional aesthetic between the conservative forms of the pre-war period and the emerging streamlined tendencies of the 1920s. The RL Sport was produced in limited numbers between 1922 and 1925, with a total RL production of approximately 2,600 units across all variants. Of these, only a small proportion were RL Sport chassis delivered for custom coachwork. Precise production figures for the Castagna-bodied examples are not recorded, and the number of surviving vehicles of this configuration remains extremely limited. No known factory records confirm the chassis number or ownership chain of the illustrated example. The RL Sport Castagna was not a competition vehicle, but it shared mechanical lineage with RL models that achieved success in events such as the Targa Florio. Its construction illustrates Alfa Romeo’s early reliance on external coachbuilders prior to the introduction of standardized factory bodies in later decades.