| Abstract | Aerodynamic drag redaction via surface engineered aircraft with structured riblet coating or the so-call sharkskin with periodic micro-ridges aligned with the direction of air flow, has been identified to be a high return-on-investment with immediate impact on GHG reductions of existing and new aircraft. It targets to have a potential drag reduction of up to 10% under turbulent flow conditions. As such, riblet technologies have been intensively developed in the past decades; Lufhansa Technik has recently successfully demonstrate the reduction of fuel burn by riblet implementation on Boeing 747 and Boeing 777 cargo planes. Nevertheless, riblet technology is not yet mature; there remain critical challenges with, for example, the material durability and manufacturing the 2D and 3D riblet designs with cost effective processing to get the coating on-aircraft application. National research Council Canada developed a new hydrophobic, erosion-resistant polyurethane coating that showed drastically improved erosion resistance against both sand particles and rain droplets, much enhanced hydrolytic stability and high resilience and mechanical properties compared to commercial erosion protective materials. To get this product to the market for the commercialisation purposes, development of low-cost continuous large-scale coating production of film type that can be readily used on aircraft surface should be established. This work focusses on the technology development and optimization of large-scale coating fabrication through continuous direct extrusion sheet cast process. First, Kinetic reaction of new patented TPU coating was investigated in terms of reactivity in order to define processing parameters using a combination technique including (Infrared spectroscopy (FTIR), Dynamic Scanning Calorimetry (DSC) and Rheology) to understand material curing temperature, gel point, crosslinking time, etc. Extracted parameters were used to develop proof of concept lab-scale coating fabrication of the new patented TPU and than extended to large-scale coating fabrication using continuous direct extrusion cast processing. Finally, some characterization on produced films was conducted in terms to evaluate the performance of produced films. |
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