PRODUCTION OF PROTOTYPE AEROFOILS USING DOUM PALM (HYPHAENE THEBAICA) LEAF STALK FIBRE-REINFORCED POLYMER COMPOSITES

ABSTRACT NACA aerofoil profiles are widely employed in designing aircraft wings, tails, propellers, and turbine and compressor blades due to their reliable aerodynamic characteristics. However, conventional aerospace materials such as steel, titanium, and magnesium alloys are relatively heavy, often compromising performance by causing low lift, high drag, excessive pitching moments, and poor stall behaviour, which increase fuel consumption and operational risks. This study addresses these limitations by developing lightweight fibre-reinforced polymer composites using Doum palm (Hyphaene thebaica) leaf stalk fibres, epoxy resin, and Calcium Sulphate Hemihydrate (CaSO₄·½H₂O). Composites were fabricated via the hand lay-up method, with epoxy resin, hardener, and accelerator mixed in a 10:2:1 ratio, and fibres cut to 10 mm and incorporated at a matrix-to-fibre weight ratio of 120 g to 15 g. The mixture was poured into metal moulds to ensure uniform laminate thickness and proper fibre impregnation. NACA 4415, 2412, and 0015 profiles were designed using SolidWorks CAD software. The resulting prototypes exhibited uniform laminate thickness, smooth surfaces, and excellent structural integrity. Wind tunnel testing at a Reynolds number of 1×10⁵ showed that NACA 4415 achieved a peak lift coefficient (CL) of 1.472 at 13°, a maximum drag coefficient (CD) of 0.032 at 13°, and a peak lift-to-drag ratio (CL/CD) of 56.153 at 15°. NACA 2412 reached a peak CL of 1.259 at 13°, maximum CD of 0.059 at 14°, and CL/CD of 46.363 at 8°, while NACA 0015 attained a maximum CL of 1.033 at 12°, CD of 0.049 at 12°, and CL/CD of 39.545 at 8°. Overall, NACA 4415 demonstrated superior lift and aerodynamic efficiency, NACA 2412 showed moderate performance, and NACA 0015 offered predictable but lower lift, confirming the effectiveness of Doum palm fibre composites in producing lightweight, structurally sound, and aerodynamically efficient aerofoils for high-lift applications.