A computer aided manufacturing procedure for experimental two‐dimensional aerofoils

The manufacture of experimental aerofoil sections to a specific profile is generally an expensive and lime consuming part of aeronautical research. This paper describes a computer aided manufacturing procedure that has been developed for the production, in a small research engineering workshop, of experimental wing models required for investigation of the separation of flow from an NACA 4412 aerofoil section. A 2 1/2 axis CNC vertical milling machine has been programmed with coordinates generated by computer from the NACA 4412 defined profile, to produce aerofoil sections which are then built up into a wing model.The method is fast and accurate, enabling the time and cost of manufacture to be substantially reduced, at the same time improving the accuracy and quality of the model. The procedure has been developed as a computer program and is also used as a case study teaching aid in computer aided manufacture.Table 1 Polynomial constants for the profile surfaceFig. 1 caption: Basic ordinates of NACA family acrofoil [from Jacobs et al. (5)]Fig. 2 caption: Characteristic features of the NACA 4412 aerofoil sectionFig. 3 caption: Aerofoil section part surfacesFig. 4 caption: Aerofoil machining detail (dimensions in mm)Fig. 5 caption: Top: blank in fixture prior to machining Bottom: finished aerofoil sectionFig. 6 caption: Finished model wing assembly

Keywords

Aerospace engineering