CRP Technology collaborated with the Department of Aerospace Science and Technology of the Politecnico di Milano (PoliMi) on the construction of parts for the aeroelastic wind tunnel demonstrators for “Aeroelastic Flutter Suppression (AFS)” e “GLAMOUR” projects.
The AFS project was launched by PoliMi and the University of Washington to test different active control system technologies aiming to attain Active Flutter Suppression.
The GLAMOUR project was focused on technological optimization and experimental validation of Gust Load Alleviation (GLA) control systems for an advanced Green Regional Aircraft manufactured by Leonardo Aircraft Division.
The contribution of CRP Technology involved the manufacturing of the external aerodynamic segments of the two wind tunnel demonstrators for both projects.
CRP Technology used professional 3D printing (selective laser sintering technology) and Carbon-composite Windform® XT 2.0 from its range of composite materials for LS, the Windform® TOP-LINE. Windform® XT 2.0 was also used by CRP Technology to create the horizontal tail of the wind tunnel demonstrator for the AFS project.
Aerodynamic features correct and enhance the external shape of the wing and, at the same time, transmit the aerodynamic loads to the internal structure.
Prior to professional 3D printing, the aerodynamic sections of the wings were produced by carbon or glass fiber fabrics dry lamination, which were wrapped Styrofoam blocks suitably cut to match the wing’s shape.
This manufacturing process required much longer times and yielded lower quality surface finish.
Professional 3D printing has revolutionized the entire process of construction and verification of the parts allowing the following: faster production speed and possibility of optimizing the internal shape of these aerodynamic sections, allowing to make them as lightweight and stiff as possible.
Through Selective Laser Sintering provided by CRP Technology, the PoliMi team was able to transfer resources from the construction phase to the design phase, obtaining better optimized components.
The wing components had to be lightweight, stiff, with parts characterized by thin layers (to obtain the lightest possible components, often the CAD design of the aerodynamic sectors is pushed to the limits) and with a smooth external surface.
During the test phase, the aerodynamic sections are not usually subjected to high stress since they do not form the primary structure of the aircraft, but perform a very important task: they transmit efficiently the aerodynamic forces to the flexible spar, acting as interface structure between the fluid (incoming air) and the internal structure of the wing. Therefore, it was fundamental that a good surface finish was achieved on the parts exposed to the incoming wind. The components were of reduced weight and were able to transmit the aerodynamic loads on the wing’s longitudinal spar.
Regarding the AFS project, Windform® XT 2.0 composite material combined with the LS technology, allow the wing sections to be designed including the elements for the connection to the main spar and, in case of the control surfaces, the hinges and the electric drivers. Regarding the GLAMOUR project, Windform® XT 2.0 – thanks to the Carbon fibers – allows the combination of the vibration frequency targets together with the forced mass constrains.