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Comparison between FDM model and steel model as wind tunnel testing models

This paper describes research into the feasibility of using FDM rapid prototyping in the wind tunnel testing models fabrication. Two models were evaluated. The first model was fabricated from Steel 17-4PH H900 by a CNC machining technique. The other model had the same CAD section but was fabricated by the fused deposition method (FDM) process. A third model was produced by sanding the steel model to reduce surface roughness by covering the full model in a layer of silicon carbide particles called "grit". The times and costs required for model fabrication were compared. Aerodynamic characteristics of both models were measured in 0.3 to 1.3 Mach and the results were compared. It is shown in this paper that there is an acceptable agreement between aerodynamic characteristics of FDM model and that of metal model. The use of FDM method rather than metal models makes a rewardable reduction in production time and cost.