The scarcity of fossil fuels has led to the development of solar-powered aircraft. The development requires a study of the aerodynamics of the aircraft while conventionally this method is complex and impractical. This is what prompts the author to analyze the design of the UAV solar powered plane using Ansys 18.0. This study aims to get the take-off speed of the initial design and / or modification if needed.. The analysis was carried out on the design of the UAV solar powered plane that had been made previously using 3D drawing software which in this study used Solidworks 2015. Numerical simulation of aerodynamics was carried out using ANSYS Fluent 18.0 to the design. The results obtained and analyzed from the simulation are lifts, drag, pressure, air velocity, and turbulence around the aircraft. The results of this study are the value of lifts and drag on the initial design and the modified design of the aircraft. This value affects the minimum take-off speed in the initial design and the modified design. The initial aircraft design assuming an initial weight of 1.4 kg requires a speed of 16-17 m/s to be able to fly while the modified design where the aircraft wingspan is extended by 19 cm each side requires a speed of 13-14 m / s to be able to air.