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The purpose of this paper is to analyze the aerodynamic improvements obtained in a wing section with a NACA 0018 airfoil manufactured using the fused deposition modeling (FDM) technique with regard to a smooth surface made by milling. The creation of micro-riblets on the surface of the airfoil, due to the deposition of the material layer by layer, improves the general aerodynamic performance of the parts, provided that the riblets are parallel to the flow line. The incidence of the thickness of the thread deposited in each layer – to be the variable on which the geometry of the riblets is based – was studied.

The wing section was designed using 3D software. Three different models were designed by rapid prototyping, using additive and subtractive manufacturing. Two of the profiles were manufactured using FDM varying the thickness of the layer to be able to compare the aerodynamic improvements. The third model was manufactured using a subtractive rapid prototyping machine generating a smooth surface profile. These three models were tested inside the wind tunnel to be able to quantify the aerodynamic efficiency according to the geometry and the riblets size.

The manufacture of an aerodynamic profile using FDM provides, in addition to the lightness and the ability to design parts with complex geometries, an improvement in the aerodynamic efficiency of 10 per cent compared with profiles with a smooth surface.

With the aerodynamic advantage gained through the use of FDM positions, the additive manufacturing serves as an excellent alternative for the manufacture of lightweight aerodynamic parts, with low structural loading and with low Reynolds number (∼5·105). This technological advantage would be applied to the UAV (unmanned aerial vehicle) industry.

The study carried out in this article demonstrates that the use of FDM as a manufacture process of end-used parts that are subject to movement generates an additional advantage that had not been considered. The additive manufacturing allows us to directly manufacture riblets by creating the necessary surface so as to reduce the aerodynamic drag.

This paper aims to review the history of Roldós y Compañía, one of the oldest advertising agencies in the world and the oldest currently operating. This research aims to highlight the importance of this agency and its founder, Rafael Roldós Viñolas – the first documented advertising agent in Spain to this day – in shaping the emerging Spanish advertising industry at the end of the 19th century.

The methodology used in this paper is based on a review of period and contemporary literature, as well as on newspaper sources and documents from the private archive of Roldós, S.A.

In its early years, the agency’s participation in two of the most significant events for the modernization of the city of Barcelona, the Universal Exhibition of 1888 and the International Exhibition of 1929; as well as the ideation and implementation of several urban projects with the aim of finding new formulas and advertising media are factors that make it one of the most important in the country. In 1929, the alliance Roldós-Tiroleses, S.A. de Publicidad, the first great merger of advertising agencies in Spain, which lasted three years, was led. The outbreak of the Civil War and the subsequent post-war period marked a few years of business irregularities and advertising silences that gave instability to its activity. During the last third of the 20th century, the agency was immersed in the generalized advertising euphoria around the world. With the arrival of North American agencies in Barcelona and the consequent business movements, Roldós, S.A. specializes in the processing of advertisements and media planning. The 21st century began with important changes in the media planning sector, and the agency was forced to restructure its services and organizational structure. In 2022, it celebrates 150 years of uninterrupted activity, recognized by the country’s business sector.

This research aims to internationalize the history of the Roldós y Compañía agency, so that it can be studied together with other names of Anglo-Saxon advertising pioneers who were contemporaries of Rafael Roldós.

Scientific research on the history of advertising agencies, especially in Spain, is scarce, so this paper aims to help fill this gap.