This paper conducts a comprehensive analysis of the KAYABU aerofoil, optimised for low-altitude subsonic solar-powered Unmanned Aerial Vehicles (UAVs). It benchmarks this aerofoil against the W.E 3.55–9.3 reference, known for subsonic solar UAVs. Performance metrics like lift-to-drag ratio, power factor, maximum lift, and stall angle are assessed. At a chosen Reynolds number of 165,000 which is relevant to the operating conditions of the UAV, Computational simulations using Xfoil and XFLR5 and wind tunnel experiments were used to validate the analysis. Results highlight KAYABU's superiority with a 1.2% boost in lift-to-drag ratio, a 16.5% rise in power factor for enhanced range and endurance, and a 40% improvement in stall angle for better stability. KAYABU also maintains lift post-stall, improving stability, and achieves an 11.6% lift increase. Experimental validation closely aligns with simulations, with an 8.7% power factor and 2.6% lift-to-drag ratio deviation. KAYABU's superior performance in subsonic UAVs enhances endurance, manoeuvrability, and mission success. This study advances knowledge and informs future solar UAV development.